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': 'Drug of choice in theophylline poisoning: \nSelect and explain. \nA. Coisone, B. Propranolol, C. Thyroxine, D. Phenobarbitone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Propranolol', 'role': 'assistant'}]