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': 'All or none law refers to: \nSelect and explain. \nA. Action potential, B. Resting potential, C. Membrane potential, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Action potential', 'role': 'assistant'}]