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]: Copper is ____ times higher in dog liver than in human liver.\Question: Choose the right answer from options given a) three b) ten c) six d) one
[EX A]: b

[EX Q]: Ants have ____ noses.\Question: Choose the right answer from options given a) zero b) eight c) five d) three
[EX A]: c

[EX Q]: Many sources estimate that ____ in every four girls has been sexually abused.\Question: Choose the right answer from options given a) seven b) one c) zero d) eight
[EX A]:
b