A committee of four members is to be formed from the following individuals: P, Q, R, S, and T. The selection criteria are: 1) P and Q cannot be selected together. 2) R must be included if S is included. 3) T can be included only if P is not included. Which of the following combinations is valid?
From the set of items: X, Y, Z, A, and B, the following rules apply: 1) X and Y cannot be selected together. 2) If Z is selected, A must also be selected. 3) B can only be selected if Y is not selected. Which selection is permissible?