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: Dental
[{'content': 'RCT treated roots with well filled post and core, has a\nperiapical radiolucency \nSelect and explain. \nA. Apicoectomy and retrograde filling with silver, B. Periapical curettage & apicoectomy, C. Retreat and filling with guttapercha, D. None of above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]