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': 'Vasopressor of choice in hypotension produced during sub–arachnoid – \nSelect and explain. \nA. Ephedrine, B. Mephenteramine, C. Adrenaline, D. Dopamine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: "Ephedrine, a mixed adrenergic agonist, provides more appropriate therapy".\n—Miller', 'role': 'assistant'}]