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': 'Atomic number of tungsten \nSelect and explain. \nA. 42, B. 181, C. 74, D. 82', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Answer: c) 74', 'role': 'assistant'}]