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: Anaesthesia
[{'content': 'Vapour concentration in a breathing system is monitored by all except \nSelect and explain. \nA. Infrared gas analysis, B. Gas chromatography, C. Ultraviolet gas analysis, D. Paramagnetism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mass spectrometry, infrared gas analysis, ultraviolet gas analysis and paramagetism are used to monitor vapour concentration in a breathing system.', 'role': 'assistant'}]