This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rheumatoid Arthritis, Subject name: Medicine
[{'content': 'HLA-DR4 is a marker of - \nSelect and explain. \nA. Rheumatoid arthritis, B. Sarcoidosis, C. Sero-negative gouty arthritis, D. Psoriasis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Rheumatoid arthritis DR4 is associated witho Extra-articular rheumatoid arthritiso Hydralazine-induced femal systemic lupus erythematosuso Pemphigoid gestationaliso Pemphigus foliaceuso Obstructive hypertrophic cardiomyopathyo IgA nephropathy", 'role': 'assistant'}]