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]: Pups get their sight in about ____ days.\Question: Choose the right answer from options given a) five b) six c) ten d) nine
[EX A]: c

[EX Q]: Astronomers fall in ____ classes - professionals and amateurs.\Question: Choose the right answer from options given a) two b) four c) six d) zero
[EX A]: a

[EX Q]: Mites can complete their life cycle in ____ to eight days depending on temperature.\Question: Choose the right answer from options given a) seven b) ten c) two d) five
[EX A]:
d