This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nerve Physiology, Subject name: Physiology
[{'content': 'All or none phenomenon is a feature of - \nSelect and explain. \nA. Action potential, B. Local potential, C. Electronic potential, D. Post-synaptic potential', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Action potential", 'role': 'assistant'}]