Excitatory postsynaptic potential (EPSP) occurs because the postsynaptic membrane improves permeability to which of the following ions
A、Na＋ and K＋, especially Na＋
B、Na＋and K＋, especially K＋
C、K＋ and Cl－ , especially Cl－
D、K＋and Cl－ , especially K＋