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
Most common site of osteogenic sarcoma is - 
Select and explain. 
A. Femur, upper end, B. Femur, lower end, C. Tibia, upper, D. Tibia, lower end
B: Femur, lower end
Answer: B: Femur, lower end 
Explanation: The most common site of involvement is metaphysis of long bone around knee : -
Lower end of femur (45%).
Upper end of Tibia (25%)