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').

Q: Stable oxygen has eight protons and ____ neutrons.\Question: Choose the right answer from options given a) eight b) ten c) three d) zero

A: a
****
Q: Smallmouth bass grow to ____ inches in their first growing season.\Question: Choose the right answer from options given a) five b) four c) seven d) ten

A: a
****
Q: Cats have ____ taboos about mating with siblings or even their offspring.\Question: Choose the right answer from options given a) no b) zero c) four d) six

A:
a
****