This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia Machine, Subject name: Anaesthesia
[{'content': 'What is present day application of oxygen concentrators include:- \nSelect and explain. \nA. Domicillary use, B. Supplying ambulance, C. Supplying anesthesia medicine, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Oxygen concentrators are widely used to provide oxygen-enriched gas for multiple use: i. Domicillary use ii. Remote locations iii. For oxygen pipeline supply iv. Anesthesia machine', 'role': 'assistant'}]