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: Microbiology
[{'content': 'PML is caused by- \nSelect and explain. \nA. CMV, B. Papova virus, C. HIV, D. Polio virus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: JC virus, which is a polyomavirus belonging to Papovaviridae family, causes progressive multifocal leucoencephalopathy (PML).', 'role': 'assistant'}]