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:
Centrifugal pumps can usually handle up to about ____ percent by volume of air.\Question: Choose the right answer from options given a) one b) five c) eight d) seven

Ex Output:
b


Ex Input:
Cows have four stomachs, and the first ____ yield merchantable tripe.\Question: Choose the right answer from options given a) two b) five c) zero d) three

Ex Output:
d


Ex Input:
Female bilbies have a backward-opening pouch with ____ nipples.\Question: Choose the right answer from options given a) no b) two c) five d) eight

Ex Output:

d