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: Surgery
[{'content': 'Bupivacaine, a local anaesthetic agent used in the dentistry in the concentration of: \nSelect and explain. \nA. 2%, B. 4%, C. 5%, D. 0.50%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]