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': 'The commonest cause of acute mesentric adenitis is - \nSelect and explain. \nA. Tuberculosis, B. Brucellosis, C. Pneumococcal infection, D. Idiopathic', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Idiopathic", 'role': 'assistant'}]