premise: Exactly seven products—P, Q, R, S, T, W, and X—are each to be advertised exactly once in a section of a catalog. The order in which they will be displayed is governed by the following conditions: Q must be displayed in some position before W. R must be displayed immediately before X. T cannot be displayed immediately before or immediately after W. S must be displayed either first or seventh. Either Q or T must be displayed fourth. If R is displayed sixth, then which one of the following must be displayed fifth?
hypothesis: P