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': 'In which of the following conditions acquired (secondary) megacolon is seen? \nSelect and explain. \nA. Fissure in-ano, B. Complete absence of parasympathetic ganglion cells, C. Absence of sympathetic ganglion cells, D. Rectal malignancy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]