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': 'Xylocaine strength used in dentistry is \nSelect and explain. \nA. 2%, B. 5%, C. 8%, D. 10% c', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]