This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ohopedics Oncology, Subject name: Orthopaedics
Peak incidence of osteosarcoma occurs at:- 
Select and explain. 
A. 2nd decade, B. 3rd decade, C. 5th decade, D. 6th decade
A: 2nd decade
Answer: A: 2nd decade 
Explanation: * The most common bone tumor of 1st decade is Ewing's sarcoma.* The most common bone tumor of 2nd decade is osteosarcoma.* Both osteosarcoma and Ewing's sarcoma peak in 2nd decade (10-20 years of age).