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: Anatomy
[{'content': 'Superior mesenteric aery supplies: \nSelect and explain. \nA. Colon, B. Anus, C. Rectum, D. Descending colon', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Colon', 'role': 'assistant'}]