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: Surgery
Which of the following malignancy is a variant of Giant cell tumor? 
Select and explain. 
A. Ossifying fibroma, B. Non ossifying fibroma, C. Osteosarcoma, D. Chondroblastoma
D: Chondroblastoma
Answer: D: Chondroblastoma 
Explanation: "A chondroblastoma is a rare, usually benign, tumor of bone that accounts for approximately 1% of all bone tumor. In 1931, Codman classified it as a chondromatous variant of giant cell tumors, when he described these lesions in proximal humerus. A decade later, Jaffe and Lichtenstein renamed the Codman tumor a benign chondroblastoma emphasizng the chondroblastic genesis of the lesion and to distinguish it from the classic giant cell tumor of bone.