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
Which valve is least affected in Rheumatic fever ? 
Select and explain. 
A. Pulmonary valve, B. Tricuspid valve, C. Mitral valve, D. Aortic valve
A: Pulmonary valve
Answer: A: Pulmonary valve 
Explanation: None