A four-person congressional committee is to be formed consisting of two senators and two representatives. The senators are to be chosen from W, X, Y, and Z; the representatives are to be chosen from P, Q, R, and S. The committee will be chosen by the vice-president subject to the following conditions:

S will not serve on the committee unless X does.

Y will not serve on a committee with Q.

The vice-president has decided that Y or Z must be included, but neither Y nor Z is willing to serve with the other.

A. Which of the following could be the fourth member of a committee that already consists of R, W, and Y?

B. If neither P nor R is assigned to the committee, which two senators must be on the committee?

C. Which of the following could be the other three members of a committee that includes Y?

D. If the vice-president chooses S to be on the committee, which of the following CANNOT be on the committee?

E. If Q is chosen to be on the committee and X is not chosen, how many different committees could be formed?