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]: Sexual maturity is reached at about ____ years of age.\Question: Choose the right answer from options given a) five b) ten c) no d) two
[EX A]: d

[EX Q]: Mothers usually give birth to one, two, or ____ babies at a time.\Question: Choose the right answer from options given a) three b) zero c) five d) ten
[EX A]: a

[EX Q]: Most national flags use one or more of only ____ basic colors.\Question: Choose the right answer from options given a) two b) nine c) seven d) ten
[EX A]:
c