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').

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

[EX Q]: Centrifugal pumps can usually handle up to about ____ percent by volume of air.\Question: Choose the right answer from options given a) one b) five c) eight d) seven
[EX A]: b

[EX Q]: Breast milk is the preferred food for an infant for the first ____ to six months.\Question: Choose the right answer from options given a) nine b) two c) four d) one
[EX A]:
c