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
A 25 year old male is undergoing incision and drainage of abscess under general anaesthesia with spontaneous respiration. The most efficient anaesthetic circuiit is: 
Select and explain. 
A. Maplelson A, B. Mapleson B, C. Mapleson C, D. Mapleson D
A: Maplelson A
Answer: A: Maplelson A 
Explanation: A ie Mapleson A