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': 'Pressure of Nitrous oxide cylinder at 100% and 40% volume respectively measured by pressure gauge is: \nSelect and explain. \nA. 750 Psi and 500 Psi, B. 750 Psi and 750 Psi, C. 750 Psi and 375 Psi, D. 750 Psi and 275 Psi', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In cases of gases which are in liquid form in cylinder ( N2O) , pressure gauze shows always full till it becomes Zero Thus in case of N2O , whether cylinder has 100% or 40% volume , pressure gauze will always show 750 Psi.', 'role': 'assistant'}]