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: Unknown
[{'content': 'Mapleson’s classification of anesthetic breathing system \nSelect and explain. \nA. Describes four systems A, B, C, D, B. Classifies the Bain system as Mapleson, C. Describes the T-piece as M, D. Describes the T-piece system as requiring a fresh gas flow rate of 1.5 – 2 times the minute volume', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The Mapleson D may be described as a co-axial modification of the basic T-piece system, developed to facilitate scavenging of waste anaesthetic gases.\nCircuit', 'role': 'assistant'}]