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:
Earthworms have ____ pairs of hearts.\Question: Choose the right answer from options given a) seven b) five c) one d) no

Ex Output:
b


Ex Input:
Fruit trees are usually safe after ____ years.\Question: Choose the right answer from options given a) five b) four c) no d) three

Ex Output:
d


Ex Input:
Many family lines travel at least ____ generations, and some for more than sixty generations.\Question: Choose the right answer from options given a) zero b) four c) seven d) ten

Ex Output:

d