This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Peritoneum, Subject name: Surgery
[{'content': "Ormond's disease is: \nSelect and explain. \nA. Idiopathic lymphadenopathy, B. Retractile testis, C. Idiopathic retroperitoneal fibrosis, D. Idiopathic mediastinitis", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: c (Idiopathic retroperitoneal fibrosis)Ref: Bailey & Love, 24th ed, p. 1151, T 67.16 & 23rd ed, p. 1024, T 56.9', 'role': 'assistant'}]