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]: Digital bandwidth enables signal to be condensed as a five to ____ ratio.\Question: Choose the right answer from options given a) one b) nine c) seven d) six
[A]: a


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


[Q]: Pickpockets often work in teams of ____ or three.\Question: Choose the right answer from options given a) one b) two c) eight d) zero
[A]:
b