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': "65 year old Ramdeen presents with Abdominal pain and distension of abdomen. His stools were maroon coloured and he gives a past history of cerebrovascular accident and myocardial infarction. What will be the probable diagnosis - \nSelect and explain. \nA. Ulcerative colitis, B. Acute mesentric ischemia, C. Irritable bowel syndrome, D. Chron's disease", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]