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': "Acute aortic regurgitation occurs in- \nSelect and explain. \nA. Infective endocarditis, B. Ankylosing spondylitis, C. Marfan's syndrome, D. All of the above", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]