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
Dead bone appears on a radiograph as: 
Select and explain. 
A. Radiolucent, B. Radio-opaque, C. Cotton wool appearance, D. Salt and pepper appearance
B: Radio-opaque
Answer: B: Radio-opaque 
Explanation: None