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
Most common extra-oral cause of Halitosis is? 
Select and explain. 
A. Indigestion, B. Chronic Sinusitis, C. Alcohol Intake, D. Diabetes Mellitus
B: Chronic Sinusitis
Answer: B: Chronic Sinusitis 
Explanation: None