This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': "HLA B27 is NOT seen in \nSelect and explain. \nA. Ankylosing spondylitis, B. Reiter's syndrome, C. Rheumatoid ahritis, D. Psoriatic ahritis", 'role': 'user'}, {'content': "Answer: C \nExplanation: Seronegative spondyloahropathies PAIR Psoriatic ahritis Ankylosing spondylitis Inflammatory bowel disease Reactive ahritis (Reiter's syndrome) Features Absence of serum autoantibodies Associated with HLA B27 Onset before 40 years Presence of uveitis, spine/large joint peripheral ahritis", 'role': 'assistant'}]