Action Potentials Are Normally Initiated at the Axon Hillock Because

Action potentials are normally initiated at the axon hillock because

A) there is a particularly high density of voltage-gated sodium channels there.
B) threshold potential is lower there than at other sites along the plasma membrane.
C) activation of sodium channels at the axon hillock results in a particularly strong inward current and consequent depolarization.
D) all of these.
E) none of these.