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: Most children improve in three to ____ days.\Question: Choose the right answer from options given a) seven b) six c) four d) ten

A: a
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Q: Female elephants have babies about ____ years apart, and they have only one each time.\Question: Choose the right answer from options given a) eight b) one c) zero d) three

A: d
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Q: Tidal currents are periodic with a net velocity of ____ over the tidal cycle.\Question: Choose the right answer from options given a) seven b) eight c) zero d) two

A:
c
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