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]: Antibodies contain ____ pairs of protein chains.\Question: Choose the right answer from options given a) no b) two c) nine d) zero
[EX A]: b

[EX Q]: Unsafe acts cause ____ times as many accidents as unsafe conditions.\Question: Choose the right answer from options given a) no b) eight c) one d) four
[EX A]: d

[EX Q]: Normal bone has ____ layers.\Question: Choose the right answer from options given a) seven b) nine c) six d) two
[EX A]:
d