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': 'β-blockers with intrinsic sympathomimetic properties a) Propranolol b) Oxprenolol c) Pindolol d) Esmolol e) Butoxamine \nSelect and explain. \nA. ab, B. ae, C. ad, D. bc', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]