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: Pharmacology
All of the following are inhalational anesthetic agents except 
Select and explain. 
A. Halothane, B. Ketamine, C. Enflurane, D. Isoflurane
B: Ketamine
Answer: B: Ketamine 
Explanation: None