This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Membrane Potentials and Action Potentials, Subject name: Physiology
[{'content': 'The hyperpolarization phase of the action potential is due to? \nSelect and explain. \nA. Opening of voltage-gated Cl- channels, B. Prolonged opening of voltage-gated K+ channels, C. Closure of resting Na-t- channels, D. Closure of Cl- channels', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) Prolonged opening of voltage-gated K+ channelsREF: Guyton\'s physiology 12th ed page 61, BRS physiology 4th ed page 11See Physiology 2013 Session 2 for "IONIC BASIS OF NERVE ACTION POTENTIAL"', 'role': 'assistant'}]