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
Which of the following occurs in epiphysis-a) Osteoclastomab) Chondroblastomac) Osteochondromad) Ewing's sarcomae) Chondrosarcoma 
Select and explain. 
A. ac, B. ab, C. ad, D. bc
B: ab
Answer: B: ab 
Explanation: Epiphvseal tumors : - Chondroblastoma, Giant cell tumor (osteoclastoma), Clear cell chondrosaroma.