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: Medicine
[{'content': 'The drug which can be used to delay the progression of aoic dilatation in marfan syndrome is: \nSelect and explain. \nA. Propranolol, B. Vitamine E, C. ACE inhibitor, D. Idebenone', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Propranolol is used to lower blood pressure and thereby delay or prevent aoic dilation. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 3213', 'role': 'assistant'}]