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]: Female cats can go into heat for the first time as early as ____ months of age.\Question: Choose the right answer from options given a) four b) zero c) five d) eight
[A]: c


[Q]: All butterflies go through ____ life stages .\Question: Choose the right answer from options given a) one b) four c) zero d) five
[A]: b


[Q]: Tornadoes have ____ destructive effects.\Question: Choose the right answer from options given a) two b) nine c) four d) three
[A]:
d