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
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 ? 
Select and explain. 
A. Ulcerative colitis, B. Acute mesentric ischemia, C. Irritable bowel syndrome, D. Chron's disease
B: Acute mesentric ischemia
Answer: B: Acute mesentric ischemia 
Explanation: Ans. is 'b' ie. Acute Mesenteric ischemia