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: ENT
[{'content': 'For deviated nasal septum, surgery is required for -a) Septal spur with epistaxisb) Marked septal deviationc) Persistent rhinorrhead) Recurrent sinusitise) Prolonged DNS \nSelect and explain. \nA. abc, B. acd, C. bcd, D. abcd', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Indications for surgery\n\nPersistent unilateral nasal obstruction and recurrent headache.\nDeviation causing recurrent sinusitis or otitis media\nRecurrent epistaxis from septal spur.\nAccess for operation in polypectomy with DNS.\nAs a part of septorhinoplasty for cosmetic correction of external nasal deformities.\nAs a approach to hypophysectomy', 'role': 'assistant'}]