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: Pathology
[{'content': "ANA (antinuclear antibody) is seen in all except? \nSelect and explain. \nA. ST E, B. RA, C. Sjogren's syndrome, D. Systemic sclerosis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., RA", 'role': 'assistant'}]