Explanation

Reading the question: we have a novel task in this question: we will complete the passage! The answer choices, as you can see, are not of a format such that they can be negated or analyzed by cases. Questions that ask for you for a logical continuation tend to have this problem, so, on logical continuation questions, the second step of the Critical Reasoning Strategy will usually not be possible (e.g., the answer choices cannot be negated), and you'll have to answer the question using only a filter.

Creating a filter: We are putting something in the blank that will complete the idea that bigger airbags that go down and cover the legs will reduce serious injuries. There is already evidence on the table; what's missing? We gravitate to the charged word "serious." The study cited in the prior sentence says "a large proportion" of accidents, but says nothing about their seriousness. So, what's missing and could go in the blank would be first of all, that the air bags will work in the leg area, and secondly, something about the seriousness of the accidents. That's our filter.

Applying the filter: Which answer choices fit either of these categories? Choices (A) through (C) do not. Choice (D) does. Choice (E) might. We take a closer look at (E). (E) discusses the likelihood of severe accidents in general, but it doesn't help us figure out whether specifically the accidents that have been happening and that an air bag will stop are severe. Back to (D). Choice (D) basically tells us, "Leg injuries are serious." This fills in one of the key missing pieces of the argument. The correct answer is (D).