Since Leggett is arguing against McBride, it's important to first understand McBride's position. McBride opposes new fuel-efficiency standards that would discourage full-size car manufacture. Why? Because McBride thinks this will decrease safety: if a subcompact car crashes with a full-size car, the subcompact car's passengers are more likely to be seriously injured compared to if two full-size cars crashed.

Leggett conversely supports the new standards, because Leggett thinks discouraging full-size car manufacturing will actually increase safety. Leggett takes a different approach to safety than McBride, who considers the outcome for passengers in subcompact versus full-size cars when crashing with a full-size car. Instead, Leggett considers whether a full-size car is involved in a crash at all: there's a lower risk of serious injury if there's no full-size car involved compared to when there is a full-size car involved

Leggett's argument proceeds by accepting some of McBride's premises, particularly that the new standards will discourage full-size car manufacture, but considering the issue from a different angle that leads to a different conclusion. Leggett doesn't even contradict McBride's claim that subcompact passengers are worse off in a crash with a full-size car; Leggett just thinks that discouraging full-size cars still overall increases safety, because there's more to safety than just McBride's example.

We're looking for an answer choice that accurately describes Leggett's method of argument while not adding in anything that isn't there. We don't know if the answer will describe the argument overall or only one strategy, so the easiest approach is process of elimination. We can eliminate any answer that misrepresents what Leggett does.