1. (C)
Question Type: Unconditional
This question does not provide us with any conditional ("If") rule in the question. It asks us for a pair of applianes that Henri could use simultaneously. Thus, we will look to eliminate the four answer choices that can’t be true.
(A) The Logic Chain tells us that when the hairdryer is in use the razor is NOT in use. Eliminate it.
(B) The same thing goes for H and T. Eliminate it.
(C) When R is in use, we know that H and V are NOT in use, but we don’t know anything about T. When T is in use, we know that H and V are NOT in use, but we don’t know anything about R. Nothing so far disproves this answer, so we’ll keep it for now.
(D) When R is in use, V is NOT in use. Eliminate it.
(E) When T is in use, V is NOT in use. Eliminate it. We’re left with answer (C).