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': 'Apicoectomy is contraindicated in \nSelect and explain. \nA. Extensive bone loss, B. Over filled root canals, C. Lateral perforation at apical third, D. Is not contraindicated', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]