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 endocrinologists see patients every ____ months throughout the pregnancy.\Question: Choose the right answer from options given a) six b) two c) zero d) three

A: b
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Q: Today there are ____ UK hospitals doing heart transplants.\Question: Choose the right answer from options given a) three b) five c) six d) nine

A: d
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Q: Carbon dioxide accounts for ____ fourths of the predicted increase in the greenhouse effect.\Question: Choose the right answer from options given a) three b) six c) ten d) five

A:
a
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