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: Nematodes occur in ____ general forms.\Question: Choose the right answer from options given a) nine b) two c) seven d) ten

A: b
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Q: Songbirds have ____ sets of vocal chords.\Question: Choose the right answer from options given a) six b) two c) eight d) ten

A: b
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Q: Sexual maturity is around ____ months.\Question: Choose the right answer from options given a) four b) eight c) three d) zero

A:
b
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