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: Metals often crystallize in a ____ dimensional version of the hexagonal closest packed structure.\Question: Choose the right answer from options given a) one b) seven c) three d) eight

A: c
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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: Double pole means that there are ____ switches.\Question: Choose the right answer from options given a) ten b) three c) four d) two

A:
d
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