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: Medicine
[{'content': "A 25 year old male presents with a history of chronic diarrhea. Pathological examination reveals cryptitis and crypt abscesses. The likely diagnosis is: \nSelect and explain. \nA. Crohn's disease, B. Ulcerative colitis, C. Giardiasis, D. Microscipic colitis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Though chronic diarrhea may be found in both ulcerative colitis and crohn's disease, cryptitis and crypt abscesses are characteristic findings of ulcerative colitis. So ulcerative colitis is the single best answer of choice. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Pages 1176-84; Davidson's Principles and Practice of Medicine, 19th Edition, Pages 808-817", 'role': 'assistant'}]