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]: Cats have ____ sets of vocal cords.\Question: Choose the right answer from options given a) zero b) nine c) two d) three
[A]: c


[Q]: Young emus are very vulnerable to disease until they are about ____ months old.\Question: Choose the right answer from options given a) no b) ten c) six d) three
[A]: d


[Q]: Wolves usually rear their pups in dens for the first ____ weeks.\Question: Choose the right answer from options given a) three b) six c) zero d) seven
[A]:
b