Four members are to be nominated to a Committee from six candidates $A,B,C,D,E,F$. Rules:
(A) If $A$ is nominated, then $D$ is excluded.
(B) If $B$ is nominated, then exactly one of $E$ or $F$ must also be nominated.
(C) If $C$ is nominated, then both $D$ and $B$ must be nominated. Which set of four is possible?