Answer:
(c) Opening of voltage gated sodium channels
Explanation:
The firing of action potential leads to a quick opening of voltage-gated Na+ channels and slow opening of K+ channels. The opened voltage-gated Na+ channels allow the Na+ to enter the neuron and cause depolarization.
The interior of the cell becomes positive quickly. As the rising potential passes 0 mV, the voltage-gated Na+ channels are inactivated and the entry of the Na+ stops while the K+ channels are fully opened to repolarize the membrane again.
