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
[{'content': 'Secondary aneurysmal bone cyst arises in - \nSelect and explain. \nA. Osteoclastoma, B. Chondroblastoma, C. Fibrous dysplasia, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Most of the time (80%) aneurysmal bone cyst is primary, and no other pathology is found.\nSecondary aneurysmal bone cysts (20%) occurs when bone changes of aneurysmal bone cyst occur in a pre-existing lesion:-\n\n\nGiant cell tumors (osteoclastoma) : - Most common\xa0\xa0\xa0\xa0\xa0\xa0\nOsteoblastoma\xa0\nSimple bone cyst\nNon-ossifying fibroma\xa0\xa0\nTelangiectatic osteosarcoma\nMetastasis\nFibrous dysplasia\nPaget's disease\n\xa0Chondromyxoid fibroma\nChondroblastoma", 'role': 'assistant'}]