Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Many tortoises can retract their head, their ____ limbs and tail into the shell for protection.\Question: Choose the right answer from options given a) no b) one c) two d) four
d

Pistillate flowers have a compound ovary with ____ locules topped by three sticky, sessile stigmas.\Question: Choose the right answer from options given a) zero b) three c) six d) seven
b

Maxillary molars have two buccal cusps and ____ lingual cusps.\Question: Choose the right answer from options given a) zero b) two c) nine d) four

b