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]: Female bilbies have a backward-opening pouch with ____ nipples.\Question: Choose the right answer from options given a) no b) two c) five d) eight
[A]: d


[Q]: Angiosperms inhabit all ____ continents, as well as the oceans.\Question: Choose the right answer from options given a) five b) seven c) three d) zero
[A]: b


[Q]: Nymphs feed and mature through five instars in about ____ to eight weeks.\Question: Choose the right answer from options given a) six b) five c) seven d) zero
[A]:
a