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


[Q]: Molecules are ____ or more atoms stuck together.\Question: Choose the right answer from options given a) two b) zero c) six d) eight
[A]: a


[Q]: Scorpions also have ____ legs.\Question: Choose the right answer from options given a) eight b) zero c) nine d) ten
[A]:
a