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]: Some male fish return after just ____ years.\Question: Choose the right answer from options given a) no b) two c) one d) six
[A]: b


[Q]: Vision problems affect one in ____ school-aged children.\Question: Choose the right answer from options given a) six b) four c) seven d) one
[A]: b


[Q]: Some infectious diseases have ____ treatments that work well.\Question: Choose the right answer from options given a) nine b) no c) eight d) seven
[A]:
b