This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal obstruction, Subject name: Surgery
[{'content': 'Most common site of volvulus: \nSelect and explain. \nA. Sigmoid colon, B. Caecum, C. Transverse colon, D. Stomach', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Most common site of volvulus is Sigmoid colon.', 'role': 'assistant'}]