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]: Normal cells have ____ copies of each chromosome.\Question: Choose the right answer from options given a) two b) five c) eight d) no
[A]: a


[Q]: Paleontologists specialize in ____ main areas.\Question: Choose the right answer from options given a) eight b) five c) no d) six
[A]: b


[Q]: Scientists emphasize how critical the first ____ years of life are in terms of brain development.\Question: Choose the right answer from options given a) ten b) five c) eight d) one
[A]:
a