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: Pathology
Most common malignant bone tumor- 
Select and explain. 
A. Osteogenic sarcoma, B. Secondaries, C. Osteoma, D. Enchondroma
B: Secondaries
Answer: B: Secondaries 
Explanation: Secondaries are most common malignant bone tumor.
Osteogenic sarcoma is the most common primary malignant bone tumor.
Osteoma is most common benign bone tumor.