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': 'Propranolol is useful in all EXCEPT: \nSelect and explain. \nA. Atrial flutter, B. Parkinsonian tremor, C. Thyrotoxicosis, D. Hypertrophic cardiomyopathy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]