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 in excitable tissue is \nSelect and explain. \nA. Na+, B. K+, C. Ca++, D. Cl-', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most diffusible ion in excitable tissue skeletal muscle and nerve cell is potassium Ref: www.gradestack.com', 'role': 'assistant'}]