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
FESS means: 
Select and explain. 
A. Factual endoscopic sinus surgey, B. Functionl endonasal sinus surgery, C. Factual endonasal sinus surgery, D. Functionl endoscopic sinus surgery
D: Functionl endoscopic sinus surgery
Answer: D: Functionl endoscopic sinus surgery 
Explanation: Indications ofFESSi) Chronic bacterial sinusitis unresponsive to adequate medical treatment.ii) Recurrentacutebacteridsinusitis.iii) Polypoid rhinosinusitis (diftrse nasal polyposis)'w) Fungal sinusitis with fungal ball or nasal polypi'v) Antrochoanal polyp and Ethmoid polypvi) Mucocele of frontoethmoid or sphenoid sinus.vii) Control of epistaxis by endoscopic cautery.viii) Removal of foreign body from the nose or sinus'ix) EndoscoPicsePtoPlastY.x) Removal of benign tumours, e.g. inveedpapillomas or an$ofibromas.xi) Orbital abscess ot cellulltls nonageme,tt.xii) DacryocYstorhinostomY.:lolii) RepaltofCSFleak,xiv) Pituitarysurgeryxv) Optic nerve decomPression.xvi) Orbitd decompression for Graves disease-xvii) Control ofposterior epistaxis(endoscopicclipping ofsphenopalatine aery).xviii) Choanal atresia.