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: Females can only have four babies at ____ time.\Question: Choose the right answer from options given a) no b) one c) nine d) three
Example Output: b

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: Some nutritionists advise eating a little something every ____ hours to keep blood sugar steady.\Question: Choose the right answer from options given a) no b) four c) two d) zero
Example Output:
b