This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': 'Prolonged blockade of Eustachian tube leads to - \nSelect and explain. \nA. Atelectatic ear, B. Cholesteatoma, C. Perforation, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., All of the above Effects of acute and prolonged tubal blockageAcute tubal blockage|Absorption of ME gases|Negative pressure in ME|Retraction of TM|Transudate in ME/haemorrhage (acute OME)Prolonged tubal blockage/dysfunction|OME (thin watery or mucoid discharge)|Atelectatic ear/ perforation|Retraction pocket/ cholesteatoma|Erosion of incudostapedial jointME, middle ear; TM, tympanic membrane; OME, otitis media with effusion.", 'role': 'assistant'}]