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:
Cats can harbor a heartworm infection at any age from ____ months to seventeen years.\Question: Choose the right answer from options given a) one b) six c) nine d) three

Ex Output:
c


Ex Input:
Southern moles are six to ____ inches long and weigh three to four ounces.\Question: Choose the right answer from options given a) zero b) nine c) five d) seven

Ex Output:
d


Ex Input:
Flies normally have ____ copies of the trp gene.\Question: Choose the right answer from options given a) three b) five c) eight d) two

Ex Output:

d