This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endometriosis, Subject name: Gynaecology & Obstetrics
[{'content': 'The organ NOT involved by endometriosis: \nSelect and explain. \nA. Liver, B. Lymph nodes, C. Brain, D. Spleen', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is d, i.e. SpleenRef: Williams Gynecology, 3/ed, p23One pathological review revealed that endometriosis has been identified in all organs except spleen.', 'role': 'assistant'}]