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: Some male fish return after just ____ years.\Question: Choose the right answer from options given a) no b) two c) one d) six
Example Output: b

Example Input: Circumcisions usually heal within ____ to two weeks.\Question: Choose the right answer from options given a) one b) five c) eight d) nine
Example Output: a

Example Input: Women are five to ____ times more likely than men to suffer thyroid disorders.\Question: Choose the right answer from options given a) three b) eight c) four d) ten
Example Output:
b