Little correlation between accuracy and confidence -----> certain things affect the confidence without affecting accuracy -----> police don't let witnesses hear each other.
A is just rationalizing why they can't hear each other.
When you read this question you should be actively engaged in the question and ask..."Why can't they see each other." and then guess..."Well, maybe hearing what other people have to say screws with their testimony." And then before moving on to the questions, look at the premise and have in mind that the answer must affect the confidence and not the accuracy due to the inclusion of the second premise.