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': 'Most common heart valve involved in IV drug user is - \nSelect and explain. \nA. Mitral valve, B. Aortic valve, C. Pulmonary valve, D. Tricuspid valve', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]