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': "Which of the following is used for oxygen therapy – \nSelect and explain. \nA. Pulse oximeter, B. Nick name's catheter, C. Hudson's mask, D. Guedel's airway", 'role': 'user'}, {'content': "Answer: C \nExplanation: Hudson's mask (a non-rebreathing mask) is a low flow (variable - performance) equipment for O2 delivery.", 'role': 'assistant'}]