A Postsynaptic Neuron Has an RMP of -70mV and a Typical

Multiple Choice

A postsynaptic neuron has an RMP of -70mV and a typical threshold of -55mV.  It has three presynaptic inputs-from neurons X,Y,and Z.Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously,the postsynaptic neuron depolarizes by 1 mV. If X fires 10 times and Y fires 10 times the result will be

A) a subthreshold summation.
B) presynaptic inhibition.
C) threshold is reached and an AP is fired.
D) many APs are fired.
E) the membrane depolarizes.