In Some Cells,an Afterpotential Occurs Because

Multiple Choice

In some cells,an afterpotential occurs because

A) the sodium ions continue to enter the cell after depolarization is finished.
B) there is prolonged,elevated permeability to potassium during repolarization.
C) the sodium-potassium pump is actively exchanging ions across the membrane.
D) the extracellular Na+ ion concentration is reduced.
E) the permeability to sodium continues longer than necessary.