This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': 'Walls of the CT scanner room are coated with - \nSelect and explain. \nA. Lead, B. Glass, C. Tungsten, D. Iron', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Walls of the CT scanner room are coated with Lead', 'role': 'assistant'}]