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
Characteristic of benign tumour of lung in x-ray is 
Select and explain. 
A. Nodule of 3.5 cm, B. Spiculated margin, C. Cavitation, D. Popcorn calcification
D: Popcorn calcification
Answer: D: Popcorn calcification 
Explanation: Popcorn or homogenous, concentric, Laminar calcification s/o benign lesion.