This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
[{'content': "HLA B27 histocompatibility antigen is correlated With \nSelect and explain. \nA. Sjogren's disease, B. Ankylosing spondylitis, C. Felty's syndrome, D. Scleroderma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: REF:HARRISONS PRINCIPLE&;S OF INTERNAL MEDICINE 18TH EDITION', 'role': 'assistant'}]