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: Pathology
HLA associated with rheumatoid arthritis: 
Select and explain. 
A. DR4, B. DR1, C. DR2, D. DR3
A: DR4
Answer: A: DR4 
Explanation: Table (Harrison 17th/2051): Significant HLA Class I and Class II Associations with Disease