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': 'Ulcerative colitis almost always involves the ... ? \nSelect and explain. \nA. Caecum, B. Sigmoid, C. Right colon, D. Rectum', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Rectum", 'role': 'assistant'}]