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: Gases are perhaps the best understood of the ____ states of matter.\Question: Choose the right answer from options given a) three b) five c) nine d) zero

A: a
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Q: Cows have four stomachs, and the first ____ yield merchantable tripe.\Question: Choose the right answer from options given a) two b) five c) zero d) three

A: d
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Q: State law requires every dog or cat be vaccinated at ____ months of age and annually thereafter.\Question: Choose the right answer from options given a) six b) four c) eight d) nine

A:
b
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