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: Dental
[{'content': 'Most common extra-oral cause of Halitosis is? \nSelect and explain. \nA. Indigestion, B. Chronic Sinusitis, C. Alcohol Intake, D. Diabetes Mellitus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]