This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastro-Intestinal Tract, Subject name: Pharmacology
[{'content': 'The preferred drug for controlling an acute exacerbation of ulcerative colitis is: \nSelect and explain. \nA. Prednisolone, B. Sulfasalazine, C. Mesalazine, D. Vancomycin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: - Coicosteroids are the mainstay of treatment of acute exacerbation of ulcerative colitis. - so, among the given options prednisolone is best to be used in controlling acute exacerbation of ulcerative colitis', 'role': 'assistant'}]