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
Vegetations on under-surface of A. V. valves are found in: 
Select and explain. 
A. Acute Rheumatic corditis, B. Limban Sack's endocarditis, C. Non thrombotic bacterial endocarditis, D. Chronic rheumatic carditis
B: Limban Sack's endocarditis
Answer: B: Limban Sack's endocarditis 
Explanation: Vegetations occur on the surfaces of the cusps in libman sacks endocarditis and infective endocarditis. Both surfaces may be involved in both the disease but undersurface is more commonly seen in libman sacks endocaritis. Ref: Robbins Pathologic Basis of Disease By Stanley Leonard Robbins, Ramzi Coan, 7th Edition, Page 597