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 volvulus is: \nSelect and explain. \nA. Proximal jejunum, B. Stomach, C. Cecum, D. Sigmoid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]