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 drift is commonly seen in: \nSelect and explain. \nA. Influenza B, B. H . influenza, C. Influenza A virus, D. Influenza C', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Influenza A virus', 'role': 'assistant'}]