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': 'Ischemia of which of the vessel would cause least damage? \nSelect and explain. \nA. Renal aery, B. SMA, C. IMA, D. Celiac trunk', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Occlusion of IMA does not always result in irreversible ischemia of the descending and sigmoid colon, because the marginal aery of colon usually receives an adequate supply from the left branch of the middle colic aery.', 'role': 'assistant'}]