67. The following steps refer to various stages in transmission at a chemical synapse. 1. Neurotransmitter binds with receptors associated with the postsynaptic membrane. 2. Calcium ions rush into the neuron's cytoplasm. 3. An action potential depolarizes the membrane of the presynaptic axon terminal. 4. The ligand-gated ion channels open. The synaptic vesicles release a supply of neurotransmitter into the synaptic cleft. Which sequence of events is correct? A. 1 2 3 4 5 D. 4 +3+1+25 B. 2 +3 +5+4+1 E. 5+1+24+3 C. 3 +2+5 +1 4 68.