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
Most common heart valve involved in IV drug user is - 
Select and explain. 
A. Mitral valve, B. Aortic valve, C. Pulmonary valve, D. Tricuspid valve
D: Tricuspid valve
Answer: D: Tricuspid valve 
Explanation: None