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: Surgery
[{'content': 'The effect of local anesthesia can be increased by the addition of \nSelect and explain. \nA. Adrenaline, B. Isoprenaline, C. Dopamine, D. Felypressin (synthetic vasopressin)', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]