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]: Chemical interactions are essentially electron interactions of ____ atoms.\Question: Choose the right answer from options given a) six b) no c) ten d) two
[A]: d


[Q]: Some infected people have ____ symptoms at all.\Question: Choose the right answer from options given a) four b) eight c) no d) five
[A]: c


[Q]: Studies show our brains comprehend speech at ____ to five times faster than people normally speak.\Question: Choose the right answer from options given a) four b) nine c) two d) one
[A]:
a