The Depolarization of the Presynaptic Membrane of an Axon Terminal

The depolarization of the presynaptic membrane of an axon terminal most directly causes

A) voltage-gated calcium channels in the membrane to open.
B) synaptic vesicles to fuse with the membrane.
C) an action potential in the postsynaptic cell.
D) the opening of chemically sensitive gates that allow neurotransmitter to spill into the synaptic cleft.
E) neurotransmitter to bind to receptors on the postsynaptic membrane.