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: Sexual maturity is reached at about ____ years of age.\Question: Choose the right answer from options given a) five b) ten c) no d) two

Answer: d


Question: Stable oxygen has eight protons and ____ neutrons.\Question: Choose the right answer from options given a) eight b) ten c) three d) zero

Answer: a


Question: Salamanders have less-specialized morphologies than do the other ____ orders.\Question: Choose the right answer from options given a) two b) one c) eight d) ten

Answer:
a