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: Social & Preventive Medicine
[{'content': 'Most common nosocomial infection is \nSelect and explain. \nA. Respiratory tract infection, B. Gastrointestinal tract infection, C. Urinary tract infection, D. Throat infection', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]