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: Some sources claim there are more like ____ million vertebrate animals in zoos.\Question: Choose the right answer from options given a) six b) five c) one d) three

A: b
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Q: Statistics show that within ____ years of divorce, many people marry a second time.\Question: Choose the right answer from options given a) four b) nine c) six d) three

A: d
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Q: Back problems affect ____ out of ten people at some time in their life.\Question: Choose the right answer from options given a) nine b) no c) five d) two

A:
a
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