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': 'Not true about aneurysmal bone cyst \nSelect and explain. \nA. Expansile, Blood filled cyst, B. Most common in upper end of Tibia, C. Diagnosis is by FNAC, D. Is a pseudocyst', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]