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: Gynaecology & Obstetrics
[{'content': 'Endometriosis has been identified in all organs except \nSelect and explain. \nA. Pleura, B. Spleen, C. Pericardium, D. Ureter', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Endometriosis is not found in spleen.', 'role': 'assistant'}]