When a charged conductor reaches electrostatic equilibrium, which is right?

A、On the surface of the conductor, the potential is higher at points where the charge density is higher.;
B、The potential is higher at points where the curvature of conductor surface is larger.;
C、The potential inside the conductor is higher than that on its surface.;
D、The potential difference between any point inside the conductor and any point on the surface is equal to zero.