The reason why E doesn't help is because E requires us to go one more step to explain why people aren't wearing seat belts?(because they are not obeying the law?)
http://7sage.com/lsat_explanations/lsat-37-section-2-question-17/
http://7sage.com/lsat_explanations/lsat-56-section-3-question-20/
The ... (D) without hesitation. The question stem asks "which one of ... heart disease. Furthermore, the question stem asks for "most weaken ... to (B) given the question stem?