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
Halitosis is measured with: 
Select and explain. 
A. Periotran, B. Osmoscope, C. Periodontometer, D. None of the above
B: Osmoscope
Answer: B: Osmoscope 
Explanation: None