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': 'Local Anaesthetic first used clinically – \nSelect and explain. \nA. Procaine, B. Lignocaine, C. Bupivacaine, D. Cocaine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cocaine was the first local anesthetic used by Carl Koller.', 'role': 'assistant'}]