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:
Most gerbils live three to ____ years and have few health problems.\Question: Choose the right answer from options given a) three b) four c) seven d) zero

Ex Output:
b


Ex Input:
Water is present in all ____ phases in Earth s atmosphere.\Question: Choose the right answer from options given a) six b) nine c) two d) three

Ex Output:
d


Ex Input:
Reef fish assemblages on submerged lava flows of ____ different ages.\Question: Choose the right answer from options given a) one b) ten c) three d) eight

Ex Output:

c