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': 'Which of the following is the mechanism of action of local anaesthetics? \nSelect and explain. \nA. Block Na+ channel, B. Block K+ channel, C. Open Na+ channel, D. Block Ca+ channel', 'role': 'user'}, {'content': 'Answer: A \nExplanation: "Local anaesthetics block the conduction of action potential by blocking voltage gated Na+ channels". Ref: Medical Pharmacology at a Glance By Michael J. Neal 4/e, Page 15 ; Instant Pharmacology By Kourosh Saeb Parsy, Ravi G, Assomul, Fakkar J. Khan, Kasra Saeb Parsy, Eamonn Kelly; Page 123', 'role': 'assistant'}]