In the Process of Saltatory Action Potential Propagation

In the process of saltatory action potential propagation,

A) the action potential is triggered by graded depolarization of the initial segment.
B) at threshold, sodium channels begin to open rapidly.
C) local currents depolarize the region just adjacent to the active zone.
D) local currents depolarize a sensitive spot distant from the active zone.
E) A, B, and D