This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Medicine
[{'content': "Toxic megacolon is most commonly associated with: \nSelect and explain. \nA. Ulcerative colitis, B. Crohn's disease, C. Whipple's disease, D. Reiter's disease", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Ulcerative colitisComplications of Ulcerative colitis:a. Massive hemorrhage.b. Toxic mega colon with perforation.c. Colonic epithelial dysplasia and carcinoma. The risk of neoplasia increased with duration and extend of the disease.', 'role': 'assistant'}]