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]: Elk retain their antlers for more than ____ months of the year.\Question: Choose the right answer from options given a) nine b) ten c) six d) seven
[A]: c


[Q]: Cows breed at ____ years, bulls at four.\Question: Choose the right answer from options given a) two b) three c) seven d) one
[A]: b


[Q]: Ozone is a relatively simple molecule, consisting of ____ oxygen atoms bound together.\Question: Choose the right answer from options given a) five b) four c) no d) three
[A]:
d