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]: Cows can be up to ____ times more active than normal while in heat.\Question: Choose the right answer from options given a) eight b) nine c) two d) six
[A]: a


[Q]: Sexual maturity is reached at about ____ years of age.\Question: Choose the right answer from options given a) five b) ten c) no d) two
[A]: d


[Q]: Meteorites have density ____ times that of solid rock.\Question: Choose the right answer from options given a) three b) six c) zero d) four
[A]:
a