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 seventy year old patient is posted for a surgery which is likely to last 4–6 hours. The best inhalational agent of choice for maintenance of anaesthesia in such a case is – 
Select and explain. 
A. Methoxyflurane, B. Ether, C. Trichlorethylene, D. Desflurane
D: Desflurane
Answer: D: Desflurane 
Explanation: "The rapid elimination of desflurane make it the inhalational anaesthetic of choice for elderly patients". — Morgan