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').

[EX Q]: Decapod crustaceans have ____ pairs of limbs.\Question: Choose the right answer from options given a) five b) four c) six d) seven
[EX A]: a

[EX Q]: Scorpions also have ____ legs.\Question: Choose the right answer from options given a) eight b) zero c) nine d) ten
[EX A]: a

[EX Q]: Fraternal twins develop from ____ separately fertilized ova.\Question: Choose the right answer from options given a) one b) three c) two d) seven
[EX A]:
c