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: Radiology
[{'content': 'A non-vital asymptomatic tooth with a deep carious lesion shows radio-opacity at the apex is possibly: \nSelect and explain. \nA. Cementoma, B. Condensing osteitis, C. Periapical cyst, D. Periodontitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]