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': 'Most diffusible ion across the membrane is \nSelect and explain. \nA. Cl-, B. K+, C. Na+, D. Urea', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The resting membrane potential is close to the Nernst potential for K+, the ion to which the membrane is most permeable. .', 'role': 'assistant'}]