can you explain the right answer?

Let's take a look at (A). (A) says, "The skeptic failed to consider the possibility that Debbie did not always use the same method to achieve her effect." (A) looks great because if Debbie is able to use different methods to perform the trick, it's possible that the skeptic in the stimulus could miss it every time even though the trick is sometimes done by one of the methods that he tested. Thus, (A) accurately describes a flaw in the skeptic's reasoning, so it's the correct answer choice. Does this make sense? Let us know if you have any other questions!