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:
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:
Material culture is the realm of ____ dimensional objects that make up our everyday environment.\Question: Choose the right answer from options given a) ten b) three c) six d) four

Ex Output:
b


Ex Input:
Mononucleosis usually lasts for ____ to two months.\Question: Choose the right answer from options given a) three b) seven c) one d) four

Ex Output:

c