Can a claim that's not supported be considered as an intermediate conclusion?

Can intermediate conclusions be attacked (even though they're also a premise?)

Asking due to PT 67 LR Section 4 Q24 - If we accept that If not Larocque, then Student, why would C weaken the argument?

Admin Note: https://classic.7sage.com/lsat_explanations/lsat-67-section-4-question-24/