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').

Ex Input:
Vision disorders affect one in every ____ school-age children.\Question: Choose the right answer from options given a) five b) four c) nine d) one

Ex Output:
b


Ex Input:
Nymphs feed and mature through five instars in about ____ to eight weeks.\Question: Choose the right answer from options given a) six b) five c) seven d) zero

Ex Output:
a


Ex Input:
Simple vows are a period of temporary commitment and usually lasts ____ years.\Question: Choose the right answer from options given a) no b) three c) ten d) nine

Ex Output:

b