The Following Are Events in the Transmission of a Signal

The following are events in the transmission of a signal at a chemical synapse.
1) Neurotransmitter binds with receptors associated with the postsynaptic membrane.
2) Calcium ions rush into neuron's cytoplasm.
3) An action potential depolarizes the membrane of the presynaptic axon terminal.
4) The ligand-gated ion channels open.
5) The synaptic vesicles release neurotransmitter into the synaptic cleft.
Which sequence of events is correct?

A) 1 → 2 → 3 → 4 → 5
B) 2 → 3 → 5 → 4 → 1
C) 3 → 2 → 5 → 1 → 4
D) 4 → 3 → 1 → 2 → 5