OPTIONS:
(A). It expands;
(B). looseness;
(C). hydrate their cells;
(D). Constrict them;
(E). sweating;
(F). Dehydration;
(G). They may not survive.;
(H). Damages them;
Given those answer options, answer the question: Fact 1: Caffeine is a central nervous system stimulant. Fact 2: Caffeine is a stimulant, and a stimulant constricts blood vessels. Given the two facts above, what does caffeine do to blood vessels?
A:
(D).