Why is D incorrect?

@Shiyi-Zhang, Great question. Let's look at (D) and (A). We're looking for the answer choice that explains why the pundit's argument is flawed. (D) says, "legislative compromise inevitably results in popular dissatisfaction with politicians" While this is in the argument, it isn't a flaw of the argument. Diagramming the argument, we have Competing - >Compromise - >Ineffective - >Dissatisfied Diagramming the stimulus, we see that (D) is true, so it's not a flaw of the argument. (A) says, "the apparent ineffectuality of legislative representatives is the only source of popular dissatisfaction with those representatives" It's true that ineffectuality is a large source of dissatisfaction (meaning ineffectuality is sufficient for causing dissatisfaction), but it isn't the only source/cause of dissatisfaction (the necessary condition). There could be all sorts of other causes for dissatisfaction. The pundit is mixing up the sufficient for the necessary condition, and this is exactly the flaw that (A) picks up on, making it the correct answer choice. Does this make sense? Let us know if you have any more questions!