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: Surgery
[{'content': 'Acute mesenteric lymphadenitis is caused by - \nSelect and explain. \nA. E. coli, B. α-hemolytic streptococci, C. Hemophilus, D. Yersinia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Acute mesenteric lymphadenitis is the diagnosis usually given when enlarged, slightly reddened lymph nodes are encountered at the root of mesentery along with normal appendix when a pt. suspected of appendicitis is opened. "Whether this is a single, discrete entity is unclear, since the causative factor is not known.\nSome of these patients have an infection with Y. pseudo tuberculosis or Y. enterocolitis, in which case the diagnosis can be established by culture of the mesenteric nodes or by serologic titres. Children seem to be affected more frequently than men." - Harrison', 'role': 'assistant'}]