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 of A.V. valves are found in: \nSelect and explain. \nA. Acute Rheumatic corditis, B. Limban Sack's endocarditis, C. Non thrombotic bacterial endocarditis, D. Chronic rheumatic carditis", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Libman Sacks Endocarditis) Vegetation on under-surface of AV valves are typically seen in Libman Sacks Endocarditis (SLE).', 'role': 'assistant'}]