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]: Color codes are ____ digit combinations of letters and numbers that correspond to a specific color.\Question: Choose the right answer from options given a) six b) eight c) seven d) one
[A]: a


[Q]: Pupae usually transform into adults ____ to three days later.\Question: Choose the right answer from options given a) one b) two c) no d) eight
[A]: b


[Q]: Multiracial children have ____ groups they're trying to identify with.\Question: Choose the right answer from options given a) five b) two c) zero d) six
[A]:
b