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
[{'content': 'Ketamine belongs to which of the following group of drugs ? \nSelect and explain. \nA. Phencyclidine, B. Phenols, C. Barbiturate, D. Benzodiazepine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ketamine is a phencyclidine derivative presented as a racemic mixture of R-and S-ketamine.', 'role': 'assistant'}]