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:
Some olive trees live to be ____ thousand years old.\Question: Choose the right answer from options given a) ten b) zero c) two d) seven

Ex Output:
c


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:
Many water bodies have fish with low levels of mercury, and ____ limitations on consumption.\Question: Choose the right answer from options given a) five b) eight c) ten d) no

Ex Output:

d