Why Is It Not Normally Possible for Action Potentials in the Postsynaptic

Multiple Choice

Why is it not normally possible for action potentials in the postsynaptic neuron to produce an action potential in the presynaptic neuron?

A) because the axon terminals of presynaptic neurons have no acetylcholine receptors
B) because the presynaptic neurons do not have a resting membrane potential
C) because the synaptic cleft allows the diffusion of acetylcholine in one direction only
D) because the synaptic vesicles in the postsynaptic terminal are inactive
E) both because the presynaptic neurons do not have a resting membrane potential and because the synaptic cleft allows the diffusion of acetylcholine in one direction only