This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'The plateau phase of Myocardial action potential is due to: \nSelect and explain. \nA. Eflux of Na+, B. Influx of Ca++, C. Influx of K+, D. Closure of voltage gated K+ channels', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Influx of Ca++', 'role': 'assistant'}]