Of Those Listed, Which Event Occurs First Following a Depolarising

Multiple Choice

Of those listed, which event occurs first following a depolarising stimulus applied to the presynaptic membrane of an axon terminal?

A) Voltage-gated calcium channels in the membrane open.
B) Synaptic vesicles fuse with the membrane.
C) The postsynaptic cell produces an action potential.
D) Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft.