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:
Condors become sexually mature at about five or ____ years of age and mate for life.\Question: Choose the right answer from options given a) nine b) seven c) one d) six

Ex Output:
d


Ex Input:
Nucleotides only require ____ phosphorylations.\Question: Choose the right answer from options given a) five b) three c) six d) two

Ex Output:

d