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: Scientists divide bats into ____ groups.\Question: Choose the right answer from options given a) five b) two c) one d) zero

A: b
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Q: Casinos have no windows and they have ____ clocks.\Question: Choose the right answer from options given a) six b) four c) eight d) no

A: d
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Q: Moles reach sexual maturity at about ____ months of age and breed in their first winter.\Question: Choose the right answer from options given a) ten b) two c) seven d) no

A:
a
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