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
[{'content': 'Hemangioma of the rectuma) Common tumourb) Fatal haemorrhage seenc) Ulcerative colitis like symptoms seend) Acute anal fissure \nSelect and explain. \nA. bc, B. c, C. ac, D. ad', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hemangioma of the rectum is an uncommon cause of serious hemorrhage.\nWhen localized in the lower part of the rectum or anal canal, a hemangioma can be excised.\nWhen the lesion is diffuse, or lying in the upper part of the rectum, the symptoms simulate ulcerative colitis.\nDiagnosis is often missed for a long period, or it is mistakenly thought to be a carcinoma.\nSelective angiography and embolization may be helpful, but excision of the rectum is sometimes required.', 'role': 'assistant'}]