This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Orthopaedics
[{'content': 'Ankylosing spondylitis is associated with \nSelect and explain. \nA. HLA-B27, B. HLA-B-8, C. HLA-DW4/DR4, D. HLA-DR3', 'role': 'user'}, {'content': "Answer: A \nExplanation: There is a strong correlation with HLA-B2790-95% of cases are positive for HLA-B27(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 302, 426)", 'role': 'assistant'}]