This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, Subject name: ENT
A 70-year-old male presents with hearing loss and tinnitus. On examination, he has a conductive type of deafness and a dull tympanic membrane on the right side. Lymph nodal enlargement of 3x3 cm was noted in the posterior triangle of the neck. Tympanogram revealed a type B wave. The most likely diagnosis is 
Select and explain. 
A. Middle ear tumor, B. Nasopharyngeal malignancy, C. Acoustic neuroma, D. Tuberculosis of middle ear
B: Nasopharyngeal malignancy
Answer: B: Nasopharyngeal malignancy 
Explanation: Due to the obstruction of the eustachian tube, there is a conductive hearing loss with serious or suppurative otitis media. Tinnitus and dizziness may occur. Presence of unilateral serous otitis media in an adult should raise suspicion of nasopharyngeal growth. Rarely, the tumour grows up the tube into the middle ear. (Ref: Diseases of Ear, Nose and Throat, P.L Dhingra, 7th edition, page 284)