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': 'Animal reservoir for swine influenza virus is \nSelect and explain. \nA. Field mice, B. Urban rats, C. Pigs, D. Calomys callosus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The swine flu virus H1N1 caused a localised outbreak in a militiary camp in USA.', 'role': 'assistant'}]