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: Orthopaedics
X-ray appearance of osteosarcoma are all except- 
Select and explain. 
A. Periosteal reaction, B. Codman's triangle, C. Soap-bubble, D. Sunray appearance
C: Soap-bubble
Answer: C: Soap-bubble 
Explanation: None