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

[EX Q]: Mosquitoes have ____ distinctive life stages, with the first three stages being spent in the water.\Question: Choose the right answer from options given a) four b) zero c) nine d) five
[EX A]: a

[EX Q]: Ozone is formed when ____ atoms of oxygen are bound together, instead of the normal two.\Question: Choose the right answer from options given a) three b) seven c) five d) no
[EX A]:
a