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': 'Histological features of unicameral bone cysts are-a) Blood filled cystic spacesb) Endothelial cell liningc) Fibrous tissue with cystic spacesd) Pseudocyste) Single cavity with connective tissue lining \nSelect and explain. \nA. a, B. b, C. ac, D. ce', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Unicameral bone cyst is unilocular (single cavity cyst) with very thin connective tissue lining.\nThe lining of cyst consists of flimsy fibrous tissue, often containing giant cells, osteoclasts.\nCyst contains clear fluid.', 'role': 'assistant'}]