chapterwise previous years' biology papers cbse pmt;aipmt;neet-12th

68 Pages·2017·1.16 MB·English

1
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)

Awake, Arise and Stop not
till the Goal is reached.
CONTENTS

S. NO. TOPIC PAGE NO.
CLASS 12th
REPRODUCITON
1. Reproduction in Organisms NIL
2. Sexual Reproduction in Flowering Plants 2-6
3. Human Reproduction 7-13
4. Reproductive Health 14-16
GENETICS & EVOLUTION
5. Principles of Inheritance and Variation 17-23
6. Molecular Basis of Inheritance 24-29
7. Evolution 30-33
BIOLOGY IN HUMAN WELFARE
8. Human Health & Diseases 34-39
9. Strategies for Enhancement in Food 40-42
Production
10. Microbes in Human Welfare 43-46

S. NO. TOPIC PAGE NO.
BIOTECHNOLOGY
11. Biotechnology 47-52
ECOLOGY
12. Organisms and Populations 53-56
13. Ecosystem 57-61
14. Biodiversity and Conservation 62-64
15. Environmental Issues 65-68
2
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
REPRODUCTION 7. In which one of the following pollination is
autogamous?

a) Geitonogamy b) Xenogamy
SEXUAL REPRODUCTION IN FLOWERING
c) Chasmogamy d) Cleistogamy
PLANTS
Ans. (d)

8. What would be the number of chromosomes
CBSE PRELIMS – 2009
of the aleurone cells of a plant with 42

chromosomes in its root tip cells?
1. Vegetative propagation in mint occurs by:
a) 42 b) 63 c) 84 d) 21
a) Rhizome b) Sucker
Ans. (b)
c) Runner d) Offset
9. Wind pollination is common in:
Ans. (b)
a) Legumes b) Lilies

c) Grasses d) Orchids
CBSE PRELIMS – 2010
Ans. (c)
Hint: Wind pollination - Grasses; corn
2. Apomictic embryos in Citrus arise from:
Most of the land plants use insects or
a) Diploid egg
wind for pollination.
b) Synergids
The wind and water pollinated flowers are
c) Maternal sporophytic tissue in ovule
not very colourful and do not produce
d) Antipodal cells
nectar. Lilies and orchids are colourful
Ans. (c)
flowers, so are mostly insect pollinated.
3. Wind pollinated flowers are:
Legumes are self pollinated usually.
a) Small, producing nectar and dry pollen

b) Small, brightly coloured, producing large
number of pollen grains CBSE PRELIMS – 2012
c) Small, producing large number of dry

pollen grains
10. Even in absence of pollinating agents seed-
d) Large, producing abundant nectar and
setting is assured in
pollen
a) Zostera b) Salvia
Ans. (c)
c) Fig d) Commellina
4. Transfer of pollen grains from the anther to
Ans. (d)
the stigma of another flower of the same
11. An organic substance that can withstand
plant is called:
environmental extremes and cannot be
a) Autogamy b) Xenogamy
degraded by any enzyme is
c) Geitonogamy d) Karyogamy
a) Sporopollenin b) Lignin
Ans. (c)
c) Cellulose d) Cuticle

Ans. (a)
CBSE PRELIMS – 2011 12. Both autogamy and geitonogamy are prevented in:
a) Cucumber b) Castor

c) Maize d) Papaya
5. Filiform apparatus is a characteristic feature
Ans. (d)
of: Hint:
a) Suspensor b) Egg - Cucumber has male and female flowers
c) Synergid d) Zygote both on the same plant.
Ans. (c) - Castor has male and female flowers
6. Nucellar polyembryony is reported in separate but on same plant
species of: - Maize has male and female inflorescences
a) Citrus b) Gossypium (spikelets) borne separately but on same plant
c) Triticum d) Brassica - Papaya is dioecious plant. So both autogamy
Ans. (a) and geitonogamy are prevented in it.
3
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
CBSE MAINS – 2010 CBSE MAINS – 2012

17. Plants with ovaries having only one or a few
13. Examine the figures (A – D) given below and
select the right option out of 1 – 4, in which ovules, are generally pollinated by:
all the four structures A, B, C and D are a) Birds b) Wind
identified correctly c) Bees d) Butterflies

Ans. (b)
Structures
18. Which one of the following statements is wrong?
a) Pollen grains in some plants remain
viable for months
b) Intine is made up of cellulose and pectin
c) When pollen is shed at two-celled state,
double fertilization does not take place
d) Vegetative cell is larger than generative cell
Ans. (c)
19. What is the function of germ pore?
a) Initiation of pollen tube
b) Release of male gametes
c) Emergence of radicle
d) Absorption of water for seed germination
Ans. (a)

NEET – 2013
A B C D
20. Meiosis takes place in:
a) Rhizome Sporangiophore Polar cell Globule
a) Gemmule b) Megaspore
b) Runner Archegoniophore Synergid Antheridium
c) Meiocyte d) Conidia
c) Offset Antheridiophore Antipodals Oogonium
Ans. (c)
d) Sucker Seta Megaspore Gemma cup 21. Perisperm differs from endosperm in :
mother
a) Being a diploid tissue
cell
b) Its formation by fusion of secondary
Ans. (c)
nucleus with several sperms
14. Vegetative propagation is Pistia occurs by
c) Being a haploid tissue
a) Stolen b) Offset
d) Having no reserve food
c) Runner d) Sucker
Ans. (a)
Ans. (b)
22. Monoecious plant of Chara shows occurrence

of:
CBSE MAINS – 2011
a) Upper antheridium and lower oogonium
on the same plant
15. In angiosperms, functional megaspore
b) Upper oogonium and lower antheridium
develops into:
on the same plant
a) Embryo sac b) Ovule
c) Antheridiophore and archegoniophore on
c) Endosperm d) Pollen sac
the same plant
Ans. (a)
d) Stamen and carpel on the same plant
16. What is common between vegetative
Ans. (b)
reproduction and Apomixis?
23. Which one of the following statements is
a) Both are applicable to only dicot plants
correct?
b) Both bypass the flowering phase
a) Endothecium produces the microspores
c) Both occur round the year
b) Tapetum nourishes the developing pollen
d) Both produces progeny identical to the parent
c) Hard outer layer of pollen is called intine
Ans. (d)
d) Sporogenous tissue is haploid

Ans. (b)
4
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
AIPMT – 2014 • Apogamy – Formation of sporophyte
from gametophyte without involving the
24. Geitonogamy involves:
formation and fusion of gametes.
a) Fertilization of a flower by the pollen from
• Cleistogamy – the flowers are intersexual
a flower of another plant belonging to a
and remain closed causing self-
distant population.
pollination, they do not need pollinators.
b) Fertilization of a flower by the pollen from
• Geitonogamy – the pollen grains of one
another flower of the same plant.
flower are transferred to stigma of
c) Fertilization of a flower by the pollen from
another flower belonging to either same
the same flower.
• plant or genetically similar plant. This is
d) Fertilization of a flower by the pollen from
similar genetically to autogamy which is
a flower of another plant in the same
self-pollination.
population
30. In ginger vegetative propagation occurs
Ans. (b)
through:
25. Function of filiform apparatus is to
a) Offsets b) Bulbils
a) Guide the entry of pollen tube
c) Runners d) Rhizome
b) Recognize the suitable pollen at stigma
Ans. (d)
c) Stimulate division of generative cell
31. Which one of the following statements is not
d) Produce nectar
true?
Ans. (a)
a) Pollen grains of some plants cause
26. Pollen tablets are available in the market for:
severe allergies and bronchial afflictions
a) Ex situ conservation
in some people
b) In vitro fertilization
b) The flowers pollinated by flies and bats
c) Breeding programmes
secrete foul odour to attract them
d) Supplementing food
c) Honey is made by bees by digesting
Ans. (d)
pollen collected from flowers
27. Which one of the following is wrong about
d) Pollen grains are rich in nutrients and
Chara?
they are used in the form of tablets and
a) Globule is male reproductive structure
syrups
b) Upper oogonium and lower round
Ans. (c)
antheridium
Hint: Option (c) is totally wrong as honey is
c) Globule and nucule present on the same plant
made by bees from nectar collected from
d) Upper antheridium and lower oogonium
flowers.
Ans. (d)
Option (b) is to be taken as correct as

some authors say that flowers pollinated
AIPMT – 2015 by bats have fruity odour and some
others say they may have a disagreeable

odour like that of sour milk.
28. Transmission tissue is characteristic feature of:
32. The hilum is a scar on the
a) Solid style b) Dry stigma
a) Fruit, where it was attached to pedicel
c) Wet stigma d) Hollow style
b) Fruit, where style was present
Ans. (a)
c) Seed, where micropyle was present
29. Which one of the following may require
d) Seed, where funicle was attached
pollinators, but is genetically similar to
Ans. (d)
autogamy?
33. Which of the following are the important
a) Xenogamy b) Apogamy
floral rewards to the animal pollinators?
c) Cleistogamy d) Geitonogamy
a) Nectar and pollen grains
Ans. (d)
b) Floral fragrance and calcium crystals
Hint: Xenogamy - Cross pollination between
c) Protein pellicle and stigmatic exudates
two flowers of genetically different
d) Colour and large size of flower
flowers.
Ans. (a)
5
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
AIPMT RETEST – 2015 41. Which of the following statements is not correct?
a) Insects that consume pollen or nectar

34. The wheat grain has an embryo with one
without bringing about pollination are
large, shield-shaped cotyledon known as: called pollen/nectar robbers
a) Epiblast b) Coleorrhiza b) Pollen germination and pollen tube
c) Scutellum d) Coleoptile growth are regulated by chemical
Ans. (c) components of pollen interacting with
those of the pistil
35. Filiform apparatus is characteristic feature of:
c) Some reptiles have also been reported as
a) Generative cell b) Nucellar embryo
pollinators in some plant species
c) Aleurone cell d) Synergids
d) Pollen grains of many species can
Ans. (d)
germinate on the stigma of a flower, but
36. In angiosperms, microsporogenesis and
only one pollen tube of the same species
megasporogenesis:
grows into the style
a) Occur in anther
Ans. (d)
b) Form gametes without further divisions
42. Seed formation without fertilization in
c) Involve meiosis
flowering plants involves the process of:
d) Occur in ovule
a) Budding
Ans. (c)
b) Somatic hybridisation
37. Which of the following pairs is not correctly
c) Apomixis
matched?
d) Sporulation
Mode of reproduction Example
Ans. (c)
a) Offset Water hyacinth
43. Which one of the following statements is not true?
b) Rhizome Banana a) Exine of pollen grains is made up of
c) Binary fission Sargassum sporopollenin
d) Conidia Penicillium b) Pollen grains of many species cause
severe allergies
Ans. (c)
c) Stored pollen in liquid nitrogen can be
38. Coconut water from a tender coconut is:
used in the crop breeding programmes
a) Immature embryo
d) Tapetum helps in the dehiscence of
b) Free nuclear endosperm
anther
c) Innermost layers of the seed coat Ans. (d)
d) Degenerated nucellus
NEET-2; 2016
Ans. (b)

39. Male gametophyte in angiosperms produces: 44. In majority of angiosperms
a) Egg has a filiform apparatus
a) Two sperms and a vegetative cell
b) There are numerous antipodal cells
b) Single sperm and a vegetative cell
c) Reduction division occurs in the
c) Single sperm and two vegetative cells
megaspore mother cells
d) Three sperms
d) A small central cell is present in the
Ans. (a) embryo sac
Ans. (c)
AIPMT – 2016
Hint: In angiosperms the synergids have
40. The coconut water from tender coconut filiform apparatus, but in some even the
represents: egg cell has filiform apparatus. There are 3
a) Fleshy mesocarp antipodal cells. The central cell is large in
b) Free nuclear proembryo size which has two polar nucleii.
45. Pollination in water hyacinth and water lily is
c) Free nuclear endosperm
brought about by the agency of
d) Endocarp
a) Water b) Insects or wind
Ans. (c)
c) Birds d) Bats

Ans. (b)
6
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
46. The ovule of an angiosperm is technically
equivalent to

a) Megasporangium

b) Megasporophyll
c) Megaspore mother cell
d) Megaspore

Ans. (a)

47. Study the four statements (A-D) given below
and select the two correct ones out of them:
(i) Definition of biological species was

given by Ernst Mayr.

(ii) Photoperiod does not affect
reproduction in plants.
(iii) Binomial nomenclature system was

given by R.H. Whittaker

(iv) In unicellular organisms, reproduction is
synonymous with growth.
The two correct statements are

a) (ii) and (iii) b) (iii) and (iv)

c) (i) and (iv) d) (i) and (ii)
Ans. (c)

NEET- 2017

50. Flowers which have single ovule in the ovary

and are packed into inflorescence are

usually pollinated by:

a) Water b) Bee

c) Wind d) Bat
Ans. (c)
51. Functional megaspore in an angiosperm

develops into:

a) Ovule b) Endosperm
c) Embryo sac d) Embryo
Ans. (c)

52. Double fertilization is exhibited by:

a) Gymnosperms b) Algae

c) Fungi d) Angiosperms
Ans. (d)
53. A dioecious flowering plant prevents both:
a) Autogamy and xenogamy

b) Autogamy and geitonogamy
c) Geitonogamy and xenogamy
d) Cleistogamy and xenogamy
Ans. (b)

54. Attractants and rewards are required for

a) Anemophily b) Entomophily
c) Hydrophily d) Cleistogamy
Ans. (b)
7
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
HUMAN REPRODUCTION 5. Given below is a diagrammatic sketch of a
portion of human male reproductive system.
CBSE PRELIMS – 2009 Select the correct set of the names of the
parts labelled A, B, C, D:

1. Which one of the following is the correct
matching of the events occurring during
menstrual cycle?
(a) Development Secretory phase and
of corpus increased secretion of
luteum progesterone.
(b) Menstruation Breakdown of myometrium
and ovum not fertilized.

(c) Ovulation LH and FSH attain peak
A B C D
level and sharp fall in the
a) Vas Seminal Bulboure- Prostate
secretion of progesterone.
deferens vesicle thrall gland
(d) Proliferative Rapid regeneration of
b) Ureter Seminal Prostate Bulboure-
phase myometrium and maturation
vesicle thral gland
of Graafian follicle.
c) Ureter Prostate Seminal Bulboure-
Ans. (a)
vesicle thral gland
2. The correct sequence of spermatogenetic
d) Vas Seminal Prostate Bulboure-
stages leading to the formation of sperms in
deferens vesicle thrall gland
a mature human testis is:
a) Spermatid-spermatocyte-spermatogonia- Ans. (d)
6. A change in the amount of yolk and its
sperms
distribution in the egg will affect:
b) Spermatogonia-spermatid-spermatocyte-
a) Number of blastomeres produced
sperms
b) Fertilization
c) Spermatocyte-spermatogonia-spermatid-
c) Formation of zygote
sperms
d) Pattern of cleavage
d) Spermatogonia-spermatocyte-spermatid-
Ans. (d)
sperms
7. Seminal plasma in humans is rich in:
Ans. (d)
3. Foetal ejection reflex in human female is a) Glucose and certain enzymes but has no
induced by: calcium
a) Fully developed foetus and placenta b) Fructose and certain enzymes but poor
b) Differentiation of mammary glands
in calcium
c) Pressure exerted by amniotic fluid
c) Fructose, calcium and certain enzymes
d) Release of oxytocin from pituitary
d) Fructose and calcium but has no
Ans. (a)
enzymes
4. Which one of the following is the most likely
Ans. (c)
root cause why menstruation is not taking
Hint: Seminal plasma is the term used for
place in regularly cycling human female?
semen. Calcium is present in prostatic
a) Maintenance of high concentration of secretion.
sex-hormones in the blood stream

b) Retention of well-developed corpus luteum

c) Fertilisation of the ovum
d) Maintenance of the hypertrophical
endometrial lining

Ans. (c)
8
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
CBSE PRELIMS – 2010 14. The signals for parturition originate from:
a) Fully developed foetus only
8. Vasa efferentia are the ductules leading from:
b) Placenta only
a) Epididymis to urethra
c) Placenta as well as fully developed foetus
b) Testicular lobules to rete testis
d) Oxytocin released from maternal pituitary
c) Rete testis to vas deferens
Ans. (c)
d) Vas deferens to epididymis
15. The second maturation division of the
Ans. (c)
mammalian ovum occurs:
Hint: The path followed by sperms is
a) In the Graafian follicle following the first
seminiferous tubules  tubuli recti  rete
maturation division
testis  Vasa efferentia  epididmis 
b) Shortly after ovulation before the ovum
vas deferens  ejaculatory duct 
makes entry into the Fallopian tube
urethra. None of the above options is
c) Until after the ovum has been
correct. The best option seems to be (c).
penetrated by a sperm
9. The first movements of the foetus and
d) Until the nucleus of the sperm has fused
appearance of hair on its head are usually
with that of the ovum
observed during which month of pregnancy?
Ans. (c)
a) Third month b) Fourth month
16. Which one of the following statements about
c) Fifth month d) Sixth month
morula in humans is correct?
Ans. (c)
a) It has more cytoplasm and more DNA
10. Which one of the following statements about
than an uncleaved zygote
human sperm is correct?
b) It has almost equal quantity of cytoplasm
a) Acrosome serves no particular function
as an uncleaved zygote but much more
b) Acrosome has a conical pointed structure
DNA
used for piercing and penetrating the egg
c) It has far less cytoplasm as well as less
resulting in fertilization
DNA than in an uncleaved zygote
c) The sperm lysins in the acrosome dissolve
d) It has more or less equal quantity of
the egg envelope facilitating fertilization
cytoplasm and DNA as in uncleaved zygote
d) Acrosome serves as a sensory structure
Ans. (b)
leading the sperm towards the ovum

Ans. (c)
CBSE PRELIMS – 2011
11. Seminal plasma in human males is rich in:
a) Ribose and potassium 17. If for some reason, the vasa efferentia in the
b) Fructose and calcium human reproductive system get blocked, the
c) Glucose and calcium gametes will not be transported from:
d) DNA and testosterone a) Testes to epididymis
Ans. (b) b) Epididymis to vas deferens
Hint: Fructose is mainly present in secretions of c) Ovary to uterus
seminal vesicles and calcium in prostatic d) Vagina to uterus
secretions. Ans. (a)
12. Sertoli cells are found in: 18. The testes in humans are situated outside
a) Pancreas and secrete cholecystokinin the abdominal cavity inside a pouch called
b) Ovaries and secrete progesterone scrotum. The purpose served is for:
c) Adrenal cortex and secrete adrenaline a) Maintaining the scrotal temperature
d) Seminiferous tubules and provide lower than the internal body temperature
nutrition to germ cells b) Escaping any possible compression by
Ans. (d) the visceral organs
13. The part of Fallopian tube closest to the ovary is: c) Providing more space for the growth of
a) Ampulla b) Isthmus epididymis
c) Infundibulum d) Cervix d) Providing a secondary sexual feature for
Ans. (c) exhibiting the male sex
Ans. (a)
9
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
19. The figure given below depicts a a) Survival of sperm depends on the pH of
diagrammatic sectional view of the female the medium and is more active in
reproductive system of humans. Which one alkaline medium
set of three parts out of I-VI have been b) Viability of sperm is determined by its motility
correctly identified? c) Sperms must be concentrated in a thick
suspension
d) Sperm is viable for only up to 24 hours
Ans. (d)

CBSE MAINS – 2010

24. Signals from fully developed foetus and
placenta ultimately lead to parturition which

a) (II) Endometrium, (III) Infundibulum, (IV) requires the release of
Fimbriae a) Estrogen from placenta
b) (III) Infundibulum, (IV) Fimbriae, (V) Cervix b) Oxytocin from maternal pituitary
c) (IV) Oviducal funnel, (V) Uterus, (VI) Cervix c) Oxytocin from foetal pituitary
d) (I) Perimetrium, (II) Myometrium, (III) d) Relaxin from placenta
Fallopian tube Ans. (b)
Ans. (b) 25. In human female the blastocyst
a) Forms placenta even before implantation
CBSE PRELIMS – 2012
b) Gets implanted into uterus 3 days after
ovulation
20. In a normal pregnant woman, the amount of
c) Gets nutrition from uterine endometrial
total gonadotropin activity was assessed.
secretion only after implantation
The result expected was:
d) Gets implanted in endometrium by the
a) High level of circulating HCG to stimulate
trophoblast cells
endometrial thickening
Ans. (d)
b) High levels of FSH and LH in uterus to
26. Secretions from which one of the following are
stimulate endometrial thickening
rich in fructose, calcium and some enzymes?
c) High level of circulating HCG to stimulate
a) Male accessory glands
estrogen and progesterone synthesis
b) Liver
d) High level of circulating FSH and LH in
c) Pancreas
the uterus to stimulate implantation of the
d) Salivary glands
embryo
Ans. (a)
Ans. (c)

21. Signals for parturition originate from CBSE MAINS – 2011
a) Oxytocin released from maternal pituitary

b) Placenta only 27. What happens during fertilisation in humans
c) Fully developed foetus only after many sperms reach close to the ovum?
d) Both placenta as well as fully developed a) Secretions of acrosome helps one sperm enter
foetus cytoplasm of ovum through zona pellucida
Ans. (d) b) All sperms except the one nearest to the
22. The Leydig cells as found in the human body ovum lose their tails
are the secretory source of: c) Cells of corona radiata trap all the sperms
a) Intestinal mucus b) Glucagon except one
c) Androgens d) Progesterone d) Only two sperms nearest the ovum
Ans. (c) penetrate zona pellucida
23. Which one of the following statements is false Ans. (a)
in respect of viability of mammalian sperm?
10
DR. ARVIND’S BIOLOGY CLASSES
(A Unit of Med-Xel Tutorials)
28. About which day in a normal human NEET – 2013
menstrual cycle does rapid secretion of LH

(popularly called LH-surge) normally occurs? 31. What is the correct sequence of sperm
a) 14th day b) 20th day formation?
c) 5th day d) 11th day a) Spermatogonia, spermatozoa, spermatocyte,
spermatid
Ans. (a)
b) Spermatogonia, spermatocyte, spermatid,

spermatozoa
c) Spermatid, spermatocyte, spermatogonia.
CBSE MAINS – 2012
spermatozoa
d) Spermatogonia, spermatocyte, spermatozoa,
29. The secretory phase in the human menstrual
spermatid
cycle is also called: Ans. (b)
a) Luteal phase and lasts for about 13 days 32. Which one of the following is not the function
b) Follicular phase and lasts for about 13 days of placenta? It:
a) Facilitates removal of carbon dioxide and
c) Luteal phase and lasts for about 6 days
waste material from embryo.
d) Follicular phase and lasting for about 6 days
b) Secretes oxytocin during parturition.
Ans. (a)
c) Facilitates supply of oxygen and
30. Identify the human development stage
nutrients to embryo.
shown below as well as the related right place
d) Secretes estrogen.
of its occurrence in a normal pregnant Ans. (b)
woman, and select the right option for the two 33. Product of sexual reproduction generally
together. generates:
a) New genetic combination leading to
variation
b) Large biomass
c) Longer viability of seeds
d) Prolonged dormancy
Ans. (a)
34. Menstrual flow occurs due to lack of:
a) Oxytocin b) Vasopressin

c) Progesterone d) FSH
Options:
Ans. (c)
Developmental stage Site of occurrence

a) Blastocyst Uterine wall
AIPMT – 2014
b) 8-celled morula Starting point of Fallopian

tube 35. The shared terminal duct of the reproductive
c) Late morula Middle part of Fallopian and urinary system in the human male is:
tube a) Vasa efferentia b) Urethra
d) Blastula End part of Fallopian tube c) Ureter d) Vas deferens
Ans. (a) Ans. (b)
Hint: The embryo with 8-16 blastomeres is 36. The main function of mammalian corpus
luteum is to produce:
called a morula, and is present in the end
a) relaxin only
part of fallopian tube. Morula forms the
b) estrogen only
blastocyst as it reaches the uterine
c) progesterone
cavity and then blastocyst implants in
d) human chorionic gonadotropin
the endometrium. Thus, the options (b),
Ans. (c)
(c), (d) are all wrong.