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': 'Best marker for drug induced lupus is \nSelect and explain. \nA. Anti histone antibodies, B. Anti ds DNA, C. ANA, D. Anti smith Ab', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ref image - Harrison's internal medicine 20e p2517", 'role': 'assistant'}]