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': 'Tympanogram of a 70 year old male with hearing loss and tinnitus revealed a type B wave. On examination he has a conductive type of deafness and a dull tympanic membrane on the right side. Lympadenopathy was present in the posterior triangle of neck. The most likely diagnosis is: \nSelect and explain. \nA. Middle ear tumor, B. Nasopharyngeal malignancy, C. Acoustic neuroma, D. T.B of middle ear', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The presence of conductive type of hearing loss, dull tympanic membrane and type B tympanogram suggests the presence of middle ear cavity or serous otitis media. Serous otitis media in an older individual should raise the suspicion of nasopharyngeal malignancy. The presence of enlarged lymph nodes adds to the suspicion.', 'role': 'assistant'}]