Hi, B is a summation of the passage, and while it is a little weaker than I would have expected ( I would have expected the right answer to be more overtly in favor of the psychologists argument) it does sum up the authors point and the argument.
C is wrong because the psychologists in question are not making the claim that the illusion comes from our inability to make quick inferences. Their argument rests on the idea that we are able to make fast inferences.
