How will the right answer fit in terms of support and conclusion?

Only the right answer will be a conclusion guaranteed by the support in the passage.

Highlight the main conclusion in the passage, if there is one:

There is no conclusion in the passage. The right answer will be the conclusion.

[SUPPORT]. [SUPPORT]. [SUPPORT].

You should recognize the passage uses if-then rules plus a fact. That’s a really common combo of support, and you expect that to mean the conclusion will use a necessary condition. Best practice is to try to deduce a necessary condition based on the fact in the passage before you check the answers. No worries if you can’t come up with it though, since you can really aggressively eliminate answers that don’t map exactly to statements in the passage.

That said, if “none” of EM’s motors “are quiet enough to use in home appliances”, then you know that none of them are sound-insulated. That’s based on the first sentence. If they were sound-insulated, they would be quiet enough.

Map the wording of the answers to the wording of the passage:

(A) …then it is sound-insulated.

This is reversing the if-then chain from the passage, which you should recognize is a way the LSAT mixes up sufficient and necessary conditions. It doesn’t work that way. The idea is that there might be other ways a motor could qualify to be “used in institutional settings”, even if it’s not “sound-insulated”. That’s just one qualification we know about.

(B) None of the motors manufactured by EM Industries are sound-insulated.

This totally matches the deduction you might have made based on the if-then rule plus a fact in the passage. It said none of EM’s motors are “quiet enough”, but the rule says they would be quiet enough if they were “sound-insulated”. So they must not be sound-insulated.

(C) At least some…can be used in institutional settings.

Weakly worded, which you like. But we still don’t know this for sure, since the qualification for “institutional settings” that we know about is being “quiet enough”. EM’s motors don’t meet that qualification, so it could be that none of them are okay to use in these settings.

(D) …then it is sound-insulated.

Like (A), this is switching the ‘if’ and ‘then’ parts of the rule in the passage. That doesn’t work. There could be other ways a motor gets to be “quiet enough”, even if it’s not “sound-insulated”. That’s just one way the passage tells us about.

(E) None of the motors manufactured by EM Industries can be used in institutional settings.

You’d only know that for sure if there was a requirement for “institutional settings” that EM’s motors fail. But there is no such requirement in the passage. There’s just a condition that would guarantee it, the thing about being “quiet enough”. Just because the motors aren’t quiet enough doesn’t mean they can’t qualify for institutional settings in some other way the passage doesn’t mention. Do you feel like a lawyer yet?

(B) is the correct answer.