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': 'Commonest site of ischemic colitis \nSelect and explain. \nA. Hepatic flexure, B. Splenic flexure, C. Transverse colon, D. Sigmoid colon', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]