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': 'Reactionary hemorrhage occurs after extraction\nbecause of \nSelect and explain. \nA. Broken roots, B. High blood pressure, C. Sharp interdental septum, D. Gingival laceration', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]