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: 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: Astronauts sleep only ____ hours each night, on average.\Question: Choose the right answer from options given a) six b) one c) four d) seven

A: a
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Q: Bipolar depression is the more serious of the ____ types.\Question: Choose the right answer from options given a) five b) four c) two d) nine

A:
c
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