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
The following chest X-ray findings are all suggestive of malignancy except: 
Select and explain. 
A. Umbilicated surface, B. Spiculated surface, C. Peripheral cavitation, D. Diffuse calcification
D: Diffuse calcification
Answer: D: Diffuse calcification 
Explanation: Ans. Diffuse calcification