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

A: a
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Q: Unsafe acts cause ____ times as many accidents as unsafe conditions.\Question: Choose the right answer from options given a) no b) eight c) one d) four

A: d
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Q: Parasitism is the association of ____ such organisms.\Question: Choose the right answer from options given a) no b) two c) one d) ten

A:
b
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