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').

[Q]: 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
[A]: c


[Q]: Cooked meat freezes well for up to ____ months.\Question: Choose the right answer from options given a) four b) three c) eight d) five
[A]: b


[Q]: National research reflects that on average, a motorist keeps a vehicle for nearly ____ years.\Question: Choose the right answer from options given a) eight b) one c) three d) zero
[A]:
a