A Neuron's Repetitive Firing Rate Is Limited by an Absolute

Multiple Choice

A neuron's repetitive firing rate is limited by an absolute refractory period, during which a new action potential cannot be generated. Which event is chiefly responsible for this limit?

A) Opening of K⁺ leak channels.
B) Opening of voltage-gated Na⁺ channels.
C) Opening of transmitter-gated cation channels.
D) Inactivation of voltage-gated K⁺ channels.
E) Inactivation of voltage-gated Na⁺ channels.