The repolarization phase of an action potential is due to
There is a decrease in sodium permeability (inactivation of the sodium channels) and a delayed increased in potassium permeability during the repolarization phase of the action potential. The pump plays no direct role in the action potential.
Increasing sodium permability and increasing potassium permeability
Increasing sodium permeability and decreasing potassium permeability
Decreasing sodium permeability and an immediate increasing potassium permeability
Decreasing sodium permeability and a delayed increase potassium permeability
General physiology