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': 'Antigenic variation is not seen in: \nSelect and explain. \nA. Influenza type A, B. Influenza type B, C. Influenza type C, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Influenza type C', 'role': 'assistant'}]