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:
Uncontrolled diabetes can increase risk by up to ____ times.\Question: Choose the right answer from options given a) five b) four c) seven d) eight

Ex Output:
b


Ex Input:
Snakes have ____ eyelids or external ears.\Question: Choose the right answer from options given a) no b) nine c) zero d) three

Ex Output:

a