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': 'Which is enveloped virus - \nSelect and explain. \nA. Dengue virus, B. Norwalk virus, C. Hep A virus, D. Adenovirus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dengue virus (a member of flaviviridae) is an enveloped virus.\nAdenovirus, norwalk virus (caliciviridae) and hepatitis A virus (Picornaviridae) are non-enveloped viruses.', 'role': 'assistant'}]