The Following Steps Refer to Various Stages in Transmission at a Chemical

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 neuron's cytoplasm.
3) An action potential depolarises 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