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': 'An flu is ? \nSelect and explain. \nA. Type A, B. Type B, C. Type C, D. Type D', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Type A An flu (an influenza) is caused by Type A influenza virus with various HN strains.", 'role': 'assistant'}]