About conductors and dielectrics in electrostatic fields, which is false?

A、Thepotentialofoneconductorisconstantaslongasitschargeisconstant.;
B、Influencedbytheexternalelectricfield,thedielectricmoleculesrotateorstretch,andthecentersofpositiveandnegativechargesnolongercoincide,thenbecomeelectricdipoles.;
C、Inaspacewithadielectric,thefieldatanypointisthesuperpositionoffieldsproducedbythefreechargesandpolarizationchargesinthevacuum.;
D、Thesumofpolarizationchargesofonedielectriciszero.