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:
Birds reach sexual maturity in three to ____ years.\Question: Choose the right answer from options given a) seven b) two c) five d) six

Ex Output:
c


Ex Input:
Onion thrips experience ____ instars.\Question: Choose the right answer from options given a) three b) six c) eight d) four

Ex Output:
d


Ex Input:
Bovine colostrum is ____ times richer in immune factors than human colostrums.\Question: Choose the right answer from options given a) six b) three c) ten d) two

Ex Output:

c