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: Unknown
[{'content': 'Percentage of Xylocaine used in spinal anesthesia- \nSelect and explain. \nA. 1%, B. 2%, C. 4%, D. 5%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans - D', 'role': 'assistant'}]