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 Q]: Perennial grass takes three to ____ years before it is mature enough to produce adequate seed.\Question: Choose the right answer from options given a) five b) seven c) six d) four
[EX A]: a

[EX Q]: Most internal parasites are specific to one or ____ species.\Question: Choose the right answer from options given a) seven b) three c) two d) five
[EX A]: c

[EX Q]: Tobacco currently kills ____ million people per year.\Question: Choose the right answer from options given a) four b) zero c) two d) nine
[EX A]:
a