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': "The benign neoplasm of 'brown fat' noted in oral/ pharyngeal region is: \nSelect and explain. \nA. Lipoma, B. Hibernoma, C. Teratoma, D. Brown tumor", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]