This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2019, Subject name: Anaesthesia
[{'content': 'Which of the following induction agent causes least respiratory depression?. \nSelect and explain. \nA. Midazolam, B. Ketamine, C. Propofol, D. Thiopentone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ketamine maintains upper airway reflex and causes less depression of respiratory center compared to other agents', 'role': 'assistant'}]