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': 'The most common site of nasopharyngeal carcinoma is \nSelect and explain. \nA. Fossa of Rosenmuller, B. Palatine tonsils, C. Antrochoanal region, D. Valleculae', 'role': 'user'}, {'content': "Answer: A \nExplanation: The commonest site of origin of nasopharyngeal carcinoma is fossa of Rosenmuller in the lateral wall of the nasopharynx.\nTumor can spread to the following areas:-\n\nCranium through foramen lacerum & ovale → cranial nerves involvement (III, IV, V, VI); facial pain, and ophthalmic symptoms.\nParapharyngeal space → cranial nerves (IX, X, XI, XII) involvement, Horner's syndrome, Trismus (Pterygoid muscle).\nRetropharyngeal nodes → Neck pain & stiffness.\nEustachian tube → Serous OM.\nNose and orbit → Obstruction, epistaxis, proptosis.\nCervical nodes → Upper jugular and posterior triangle nodes enlargement.\nDistant metastasis → Lung, liver, bone.\nMiddle ear → Rarely, tumor grows up the tube into the middle ear.", 'role': 'assistant'}]