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 experts believe whining peaks around the ages of ____ or four.\Question: Choose the right answer from options given a) three b) no c) four d) seven

A: a
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Q: Youth unemployment is ____ times the adult level.\Question: Choose the right answer from options given a) one b) three c) seven d) no

A: b
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Q: Saturated bonds are when each of the carbons has ____ single bonds as in the top figure.\Question: Choose the right answer from options given a) four b) seven c) no d) ten

A:
a
****