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:
Cigarette smokers are ____ times more likely to die of lung cancer than nonsmokers.\Question: Choose the right answer from options given a) ten b) six c) four d) nine

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:
Postpartum blues are common during the ____ months after childbirth.\Question: Choose the right answer from options given a) four b) zero c) two d) three

Ex Output:

d