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: Sexual reproduction involves ____ parents, one male and one female.\Question: Choose the right answer from options given a) zero b) two c) nine d) four
Example Output: b

Example Input: Women gain ____ years per child they had.\Question: Choose the right answer from options given a) ten b) nine c) four d) two
Example Output: d

Example Input: Geckos are small lizards, usually about ____ to six inches long.\Question: Choose the right answer from options given a) four b) zero c) no d) three
Example Output:
d