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': 'The virus with smallest genome is - \nSelect and explain. \nA. Reovirus, B. Parvovirus, C. Picornavirus, D. HIV', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Smallest genome → Parvovirus\nLargest genome → Poxvirus', 'role': 'assistant'}]