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: Medicine
[{'content': "HLA B27 is associated with all except-a) Ankylosing spondylitisb) Pernicious anemiac) Behcet's syndromed) Reiter's sydrome \nSelect and explain. \nA. a, B. c, C. bc, D. ad", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]