This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'The following drug selectively acts on beta receptors \nSelect and explain. \nA. Dopamine, B. Isoprenaline, C. Nor adrenaline, D. Adrenaline', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Isoprenaline acts only on beta 1 and beta 2 receptors.', 'role': 'assistant'}]