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 ahritis is ? 
Select and explain. 
A. HLA B27, B. HLA DR 4, C. HLABI9, D. HLA DR2
B: HLA DR 4
Answer: B: HLA DR 4 
Explanation: Ans. is `b' i.e. HLA DR4