Final answer:
The binding of the neurotransmitter to structure labeled C would cause a depolarization of the postsynaptic membrane, resulting in a change in the membrane potential.
Step-by-step explanation:
The binding of a specific neurotransmitter causes ligand-gated channels on the postsynaptic membrane to open. This can lead to either excitatory or inhibitory effects on the postsynaptic membrane. In this case, the binding of the neurotransmitter to structure labeled C would cause a depolarization of the postsynaptic membrane, resulting in a change in the membrane potential.