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
Which of the following is used for oxygen therapy – 
Select and explain. 
A. Pulse oximeter, B. Nick name's catheter, C. Hudson's mask, D. Guedel's airway
C: Hudson's mask
Answer: C: Hudson's mask 
Explanation: Hudson's mask (a non-rebreathing mask) is a low flow (variable - performance) equipment for O2 delivery.