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]: Most birds have ____ toes, three that face forward and one rearward.\Question: Choose the right answer from options given a) two b) ten c) nine d) four
[EX A]: d

[EX Q]: Poles CAN occur at ____ frequency.\Question: Choose the right answer from options given a) six b) four c) zero d) eight
[EX A]: c

[EX Q]: Accountants There are ____ kinds of accountants.\Question: Choose the right answer from options given a) three b) two c) four d) ten
[EX A]:
a