As with the other Assumption Family questions, Find the Flaw questions will contain an argument core, and it's great if you notice assumptions that the author makes. The correct answer, though, will be essentially the opposite of the correct answer on a Find the Assumption, you pick an answer that articulates an assumption that is necessary to the argument. On Flaw questions, by contrast, you are looking for wording that indicates why it is flawed thinking to believe that this assumption is true.