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: Pathology
[{'content': 'After radiotherapy, extraction should be avoided for at least: \nSelect and explain. \nA. 1month., B. 2months., C. 6months., D. 12months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]