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': 'Maximum concentration of sodium channel is at \nSelect and explain. \nA. Cell body at dendrite end, B. Initial segment, C. Axon below myelin, D. Node of ranvir', 'role': 'user'}, {'content': 'Answer: D \nExplanation: At the node of Ranvier, Na channels are 2000 to 12000/sq micrometer of membrane(Ref: Textbook of physiology N Geetha 2nd edition page no.4)', 'role': 'assistant'}]