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]: Vaporization can occur in temperatures as low as ____ degrees.\Question: Choose the right answer from options given a) one b) zero c) eight d) two
[A]: b


[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]: Natural indium contains ____ isotopes.\Question: Choose the right answer from options given a) one b) eight c) two d) seven
[A]:
c