Assume a Hypothetical Postsynaptic Neuron Has Three Presynaptic Inputs, X

Multiple Choice

Assume a hypothetical postsynaptic neuron has three presynaptic inputs, X, Y, and Z.When presynaptic neurons X and Y are stimulated simultaneously, the postsynaptic neuron reaches threshold and undergoes an action potential.Yet, when presynaptic neurons X and Z are stimulated simultaneously, there is no change in potential of the postsynaptic neuron.Which of these statements describes the presynaptic neurons Y and Z

A) Presynaptic neurons Y and Z are both excitatory.
B) Presynaptic neurons Y and Z are both inhibitory.
C) Presynaptic neuron Y is excitatory, and presynaptic neuron Z is inhibitory.
D) Presynaptic neuron Y is inhibitory, and presynaptic neuron Z is excitatory.