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: Perennial grass takes ____ to five years before it is mature enough to produce adequate seed.\Question: Choose the right answer from options given a) six b) zero c) three d) no

A: c
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Q: Natural tellurium consists of ____ isotopes.\Question: Choose the right answer from options given a) six b) seven c) eight d) one

A: c
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Q: Fluorescent lamps are much more efficient than incandescent bulbs and last six to ____ times longer.\Question: Choose the right answer from options given a) nine b) ten c) eight d) four

A:
b
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