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': "Commonest cause of Ludwig's Angina is \nSelect and explain. \nA. Dental infection of canine tooth, B. Dental infection of 2nd molar teeth, C. Dental infection of 2nd premolar teeth, D. Dental infection of Incisor teeth", 'role': 'user'}, {'content': "Answer: B \nExplanation: Commonest cause of Ludwig's angina is dental infection of 2nd and 3rd molar teeth.", 'role': 'assistant'}]