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: Surgery
[{'content': 'all of the following are absolute contraindications for tooth extraction except: \nSelect and explain. \nA. Central hemangioma, B. Fistulas, C. Unstable angina pectoris, D. A v malformation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]