A team of four members: X, Y, Z, and W must be selected based on the following criteria: 1) X cannot be selected if Y is selected. 2) Z must be selected if W is not selected. Which of the following selections is valid?
Five friends, P, Q, R, S, and T, are sitting in a row. R is sitting to the left of S but not next to P. T is sitting to the right of Q. Who is sitting in the middle?