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: Aridity presents ____ main obstacles to solitary behavior.\Question: Choose the right answer from options given a) no b) three c) two d) five

A: c
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Q: Firebrat eggs hatch in about ____ weeks.\Question: Choose the right answer from options given a) ten b) one c) two d) no

A: c
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Q: Cryogenic processing involves lowering the temperature of an object to sub ____ temperatures.\Question: Choose the right answer from options given a) eight b) one c) seven d) zero

A:
d
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