This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and PNS, Subject name: ENT
Nasal polyps develop in patients with: 
Select and explain. 
A. Aspirin intolerance, B. Fungal sinusitis, C. Chronic rhinosinusitis of non-allergic origin, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Aetiology of nasal polyp formation is not well-understood. They are seen in:(i). Aspirin intolerance(ii). Allergic fungal sinusitis(iii). Chronic rhinosinusitis of both allergic and non-allergic origin(iv). Cystic fibrosis(v). Disorders of ciliary motility(vi). Churg-Strauss syndrome (asthma, fever, vasculitis and granuloma).