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': 'All of the following will produce conductive hearing loss, Except - \nSelect and explain. \nA. Otosclerosis, B. Serous otitis media, C. Endolymphatics Hydrops, D. Suppurative otitis media', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]