This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
[{'content': 'Outer membrane action potential is maintained by influx of \nSelect and explain. \nA. Na+, B. Mg3+, C. K+, D. CA2+', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Outer membrane action potential is maintained by influx of K+ Ref: guyton and hall textbook of medical physiology 12 edition page number:66,67,68', 'role': 'assistant'}]