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 volcanoes erupt for ____ to four weeks and then rest.\Question: Choose the right answer from options given a) three b) four c) one d) eight

Ex Output:
a


Ex Input:
Respiratory therapists complete two to ____ years of education.\Question: Choose the right answer from options given a) no b) one c) four d) eight

Ex Output:
c


Ex Input:
Some people produce two, three or ____ times the normal amount of insulin.\Question: Choose the right answer from options given a) zero b) nine c) four d) five

Ex Output:

c