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: Anaesthesia
[{'content': 'Local anaesthetics act by \nSelect and explain. \nA. Effecting the spinal level, B. Effecting the Na+ channel, C. Effecting the K+ channel, D. Blocking axonal transpo', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Effecting the Na+ channel', 'role': 'assistant'}]