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: Many comets have ____ tails.\Question: Choose the right answer from options given a) two b) six c) three d) one

A: a
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Q: Gestation lasts ____ months, with the birth of a single calf.\Question: Choose the right answer from options given a) three b) one c) six d) eight

A: d
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Q: Diols contain ____ -OH groups.\Question: Choose the right answer from options given a) three b) eight c) two d) seven

A:
c
****