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]: Ozone is a molecule containing ____ oxygen atoms.\Question: Choose the right answer from options given a) one b) nine c) no d) three
[A]: d


[Q]: China is reportedly in the top ____ nations in industrial output.\Question: Choose the right answer from options given a) seven b) ten c) three d) five
[A]: b


[Q]: Most caterpillars molt four or ____ times before they are full-grown.\Question: Choose the right answer from options given a) ten b) three c) six d) five
[A]:
d