This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rheumatic Fever, Subject name: Pathology
Which of the following cardiac valves is not commonly involved in rheumatic fever? 
Select and explain. 
A. Mitral, B. Aoic, C. Pulmonary, D. Tricuspid
C: Pulmonary
Answer: C: Pulmonary 
Explanation: In chronic disease the mitral valve is viually always involved. The mitral valve is affected in isolation in roughly two thirds of RHD, and along with the aoic valve in another 25% of cases. Tricuspid valve involvement is infrequent, and the pulmonary valve is only rarely affected.