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: Sound waves travel through the air in a similar manner, but in all ____ dimensions.\Question: Choose the right answer from options given a) three b) five c) nine d) one

A: a
****
Q: Vision disorders affect one in every ____ school-age children.\Question: Choose the right answer from options given a) five b) four c) nine d) one

A: b
****
Q: Trees have ____ ways to spread their seeds.\Question: Choose the right answer from options given a) no b) nine c) zero d) four

A:
d
****