This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excitation and Action Potiential, Subject name: Physiology
[{'content': 'At the end of repolarization, the nerve is hyperpolarized. How does the membrane potential return to RMP? \nSelect and explain. \nA. Action of Na+/ K+ -pump, B. Inward leakage of Na+, C. Decrease in K+ efflux, D. None of the above mechanisms', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Simultaneously with the action of the pump, there is inward diffusion of Na+ through the leaky channels (not the voltage-gated channels that cause depolarization). This inward leakage of positive charges will take the membrane potential from - 90 mV to original RMP of - 70 mV. Both the pump and the inward leakage will balance out once the potential again reaches - 70 mV.', 'role': 'assistant'}]