<prompt> The preferred drug for controlling an acute exacerbation of ulcerative colitis is:PrednisoloneSulfasalazineMesalazineVancomycin  <response>: - 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 