This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Plateau phase of cardiac muscle is due to \nSelect and explain. \nA. East Na + channel opening, B. Opeaning of Ca++Na+ channels, C. Opeaning of Slow Ca++ channels, D. Opeaning of K + channels', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ca2+ influx through more slowly opening Ca2+ channels produces the plateau phase The initial depolarization is due to Na+ influx through rapidly opening Na+ channels Repolarization is due to net K+ efflux through multiple types of K+ channels Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:491", 'role': 'assistant'}]