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: Ultrasonic liposuction fits into ____ categories.\Question: Choose the right answer from options given a) two b) seven c) nine d) one

A: a
****
Q: Ostriches have ____ stomachs.\Question: Choose the right answer from options given a) four b) nine c) eight d) three

A: d
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Q: Scientists believe there are only ____ classes of such protease enzymes.\Question: Choose the right answer from options given a) one b) zero c) three d) four

A:
d
****