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: Pharmacology
[{'content': 'The metabolic effects of sympathomimetics are mediated by \nSelect and explain. \nA. All beta-adrenergic receptors, B. Dopaminergic receptors, C. Beta 2 receptors, D. Opioid receptors', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]