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': 'Subperiosteal abscess, penetrating deep is seen after extraction of \nSelect and explain. \nA. Maxillary 3rd molar, B. Mandibular 3rd molar, C. Maxillary 1st molar, D. Mandibular 1st molar', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]