The Threshold of a Neuron Is the

The threshold of a neuron is the

A) amount of inhibitory neurotransmitter required to inhibit an action potential.
B) membrane voltage at which an axon potential will be suppressed.
C) amount of excitatory neurotransmitter required to elicit an action potential.
D) membrane voltage at which the membrane potential develops into an action potential.
E) closing of numerous sodium channels.