Thanks for the question! Take a look at the remainder of the last paragraph. We’re told that basically, people will tend to use internal factors and not external factors when explaining the behavior of others. As such, people might ignore external factors, which is what the last sentence of the paragraph tells us. This process is what the author refers to when they write about “jurors’ superficial examination of confession evidence,†since they will see possible internal motivations but not external ones. (A) encapsulates this idea, since it tells us that this phrase has to do with not properly taking into account the factors that may lead an individual to give confession evidence—not properly, in this case, because the jurors ignore the external factors. Hope this helps! Feel free to ask any other questions that you might have.