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': 'A most common organism which can contaminate crowded army camps is ? \nSelect and explain. \nA. Klebsiella, B. E. coli, C. Neisseria meningitidis, D. Staphylococcus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Epidemics of Neisseria meningitidis usually occur in closed crowded conditions like jails or army camps.', 'role': 'assistant'}]