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: Radiology
[{'content': 'The following chest X-ray findings are all suggestive of malignancy except: \nSelect and explain. \nA. Umbilicated surface, B. Spiculated surface, C. Peripheral cavitation, D. Diffuse calcification', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. Diffuse calcification', 'role': 'assistant'}]