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
True regarding osteosarcoma is - 
Select and explain. 
A. Occurs because of proliferation of osteoclasts, B. Sunray appearance in X-ray indicates new bone formation, C. Affects mainly males in 5th or 6th decade, D. Lymphtic metastasis is most common
B: Sunray appearance in X-ray indicates new bone formation
Answer: B: Sunray appearance in X-ray indicates new bone formation 
Explanation: Osteosarcoma arises from primitive bone forming cells.
Sunray appearance and Codman's triangle indicate periosteal new bone formation.
Osteosarcoma occurs in childhood or young adult (10-25 years).
Blood metastasis is most common (not lymphatic).