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:
Military service is fulfilled by voluntary enlistment, generally for a period of ____ years.\Question: Choose the right answer from options given a) four b) one c) nine d) two

Ex Output:
c


Ex Input:
Rapid growth occurs for the first ____ years of life.\Question: Choose the right answer from options given a) eight b) ten c) three d) five

Ex Output:
d


Ex Input:
Radiographs show ____ dimensional representation of three dimensional structures.\Question: Choose the right answer from options given a) nine b) one c) two d) four

Ex Output:

c