There's a mix of conditional reasoning and formal logic here, mtlwtiener. Here's a diagram of what's going on:
Students
Off Campus
Music Major
Choir
Conclusion: Music Major
Off Campus
We need an answer that will absolutely prove that conclusion. Even though some students live off campus, the music majors cannot. What do we need to say to prove that conclusion is true? We need to show that everyone living off campus is not a music major. It's the conditional reasoning we need to focus on because the formal logic use of "some" won't be strong enough to prove the much stronger conclusion about "none."
Maybe if we knew something about the members of the choir, to tie all the parts together? What if we were to say that choir members don't live off campus? Then we would know the following:
Music Major
Choir
Off Campus
Boom, conclusion proven through a conditional chain! That's what answer A does for us.
So what impact, if any, does answer E have? We already know that every music major is in the choir, so what if we also knew that everyone in the choir was a music major? Combining those two ideas would give us this:
Music Major
Choir
Does this tell us anything about where any of those people live? Nope, it would leave us still wondering how on earth the author got the idea that the music majors are not living off campus. For all we know, with this info in hand, every music major and every choir member (who are the same exact group of people) all live off campus. The answer fails to connect the ideas that need to be connected! That's why E cannot justify the conclusion.
Adam M. Tyson
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