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:
Moles breed in late winter or spring and have a gestation period of ____ to six weeks.\Question: Choose the right answer from options given a) nine b) four c) six d) five

Ex Output:
b


Ex Input:
Cows breed at ____ years, bulls at four.\Question: Choose the right answer from options given a) two b) three c) seven d) one

Ex Output:
b


Ex Input:
Scientists divide bats into ____ groups.\Question: Choose the right answer from options given a) five b) two c) one d) zero

Ex Output:

b