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: Tetrapods are animals that have ____ legs or leg-like appendages.\Question: Choose the right answer from options given a) four b) one c) ten d) six

A: a
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Q: Females can only have four babies at ____ time.\Question: Choose the right answer from options given a) no b) one c) nine d) three

A: b
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Q: Lung cancer accounts for more new cases and deaths than do the next ____ leading cancers combined.\Question: Choose the right answer from options given a) three b) two c) nine d) six

A:
a
****