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').

Example Input: Ossification begins up to ____ months before birth.\Question: Choose the right answer from options given a) nine b) seven c) three d) six
Example Output: b

Example Input: Ants have six legs, and each leg has ____ joints.\Question: Choose the right answer from options given a) nine b) zero c) two d) three
Example Output: d

Example Input: Some spiders have up to six or ____ or twelve eyes.\Question: Choose the right answer from options given a) seven b) eight c) two d) six
Example Output:
b