A debate team must consist of four debaters selected from seven candidates: A, B, C, D, Y, and Z. The following conditions apply:

• If Y is selected, B must also be selected.
• If Z is selected, D must also be selected.
• If B is selected, C cannot be selected.
• A and C cannot both be selected.
• If D is selected, A cannot be selected.

If both Y and Z are selected, which of the other debaters must be in the team with them?