premise: Exactly five movies are showing at the repertory theater this evening: a horror film, a mystery, a romance, a sci-fi film, and a western. Each movie is shown exactly once, on one of the theater's three screens: screens 1, 2, and 3. Screens 1 and 2 show two movies each, one beginning at 7 P.M. and the other at 9 P.M.; screen 3 shows exactly one movie, at 8 P.M. The following conditions apply to this evening's schedule: The western begins at some time before the horror film does. The sci-fi film is not shown on screen 3. The romance is not shown on screen 2. The horror film and the mystery are shown on different screens. If the sci-fi film and the romance are to be shown on the same screen, then which one of the following must be true of this evening's schedule?
hypothesis: The western begins at 7 P.M.