This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Anatomy
Least chances of infective endocarditis is associated with: 
Select and explain. 
A. Mild MS, B. Mild MR, C. Small ASD, D. Small VSD
C: Small ASD
Answer: C: Small ASD 
Explanation: Infective endocarditis is very rare in patients of ostium secondum atrial septal defect, unless floopy mitral valve is present .(ref Ghai 7th/390,403)