Explanation

Reading the question: the citizen makes a fairly thin argument, and the council member makes a good point in response. We're asked how the council member responds. We can see at a glance that the answer choices are of the general, logical type. It's often worth glancing at the answer choices to check their format, though you want to construct a filter before evaluating them. To match the answer choices, we'll make a general, logical prediction of the answer.

Creating a filter: we can make the following prediction of the correct answer. The citizen is assessing the value of this security program too narrowly, and the council member points out a benefit of the program the citizen hadn't considered. That's the filter: "benefit overlooked."

Applying the filter: Do any answer choices fit our prediction? Choice (A) is far off from our prediction. Choice (B) misses the main thrust of pointing out a benefit the citizen hadn't considered. And the council member says, "even if we granted that those odds didn't justify the costs," so with his main point he is specifically not arguing about the odds, as (B) indicates. Choice (C) and (E) are far off from our prediction. Choice (D) is close to our prediction, so we are left with (D).

Logical proof: we generally can't make a logical proof of our answer to a logical continuation question, but we can confirm our answer, in this case, by mapping the generalities of the answer choice back to specifics in the prompt. The council member definitely "defends the current system," and he does "point out a benefit of the system that the citizen has failed to mention"--it's that the mere presence of the checkpoint deters some people who might not have been caught. The correct answer is (D).