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: Astronauts sleep only ____ hours each night, on average.\Question: Choose the right answer from options given a) six b) one c) four d) seven

A: a
****
Q: Banks hold no excess reserves and the public holds ____ currency.\Question: Choose the right answer from options given a) seven b) zero c) no d) four

A:
c
****