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: Surgery
[{'content': 'BK virus affects which organ transplantation? \nSelect and explain. \nA. Liver, B. Kidney, C. Lung, D. Marrow', 'role': 'user'}, {'content': 'Answer: B \nExplanation: K for kidney.', 'role': 'assistant'}]