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: Earthworms have ____ pairs of hearts.\Question: Choose the right answer from options given a) seven b) five c) one d) no

A: b
****
Q: China has about ____ in four of all smokers in the world.\Question: Choose the right answer from options given a) one b) seven c) ten d) six

A: a
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Q: Some cooks work fewer than ____ days a week.\Question: Choose the right answer from options given a) nine b) five c) six d) seven

A:
b
****