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').
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Question: Water weighs about ____ pounds per gallon.\Question: Choose the right answer from options given a) seven b) ten c) zero d) nine

Answer: b


Question: Astronomers fall in ____ classes - professionals and amateurs.\Question: Choose the right answer from options given a) two b) four c) six d) zero

Answer: a


Question: Most mammalian species have between ____ and fifteen types of Toll-like receptors.\Question: Choose the right answer from options given a) six b) eight c) nine d) ten

Answer:
d