I understand that E is the correct answer choice, but since this is a sufficient assumption question, isn't E describing a necessary condition? Isn't it too strong? It says New subway cars are REQUIRED. But they're not required. They're sufficient to cause an efficient, attractive subway, which in turn is sufficient to product good economic sense, but neither new subway cars NOR having an efficient and attractive subway system is NECESSARY for good economic sense.

https://classic.7sage.com/lsat_explanations/lsat-34-section-2-question-02/