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:
Decompression illness is a continuum from ____ symptoms or signs to severe multisystem involvement.\Question: Choose the right answer from options given a) nine b) three c) no d) one

Ex Output:
c


Ex Input:
Antibodies contain ____ pairs of protein chains.\Question: Choose the right answer from options given a) no b) two c) nine d) zero

Ex Output:
b


Ex Input:
Hearing is acute by three or ____ weeks and kittens learn to determine what sounds mean.\Question: Choose the right answer from options given a) six b) four c) no d) one

Ex Output:

b