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': "Vegetations on undersurface ofA. V. valves are found in - \nSelect and explain. \nA. Acute Rheumatic carditis, B. Limban Sack's endocarditis, C. Non thrombotic bacterial endocarditis, D. Chronic rheumatic carditis", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]