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: Vision problems affect one in ____ school-aged children.\Question: Choose the right answer from options given a) six b) four c) seven d) one
Example Output: b

Example Input: Nymphs feed and mature through ____ instars in about six to eight weeks.\Question: Choose the right answer from options given a) four b) eight c) five d) no
Example Output: c

Example Input: Females are ____ times more likely to be sexually abused during childhood than males.\Question: Choose the right answer from options given a) nine b) seven c) two d) three
Example Output:
d