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]: Youth unemployment is ____ times the adult level.\Question: Choose the right answer from options given a) one b) three c) seven d) no
[A]: b


[Q]: Psychiatrists say that one in ____ people are mentally ill.\Question: Choose the right answer from options given a) one b) two c) four d) nine
[A]: c


[Q]: Butterflies possess a complex life cycle that requires ____ metamorphoses to complete.\Question: Choose the right answer from options given a) two b) four c) three d) five
[A]:
b