This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
[{'content': 'Which one of the following is the most common tumour to produce metastasis to cervical lymph nodes ? \nSelect and explain. \nA. Glottic carcinoma, B. Nasopharyngeal carcinoma, C. Carcinoma base of tongue, D. Carcinoma lip', 'role': 'user'}, {'content': "Answer: B \nExplanation: HO's triangle in supraclavicular fossa (bounded by medial and lateral ends of clavicle and point where neck meets the shoulder)is the site where metastatic nodes commonly exist in nasopharyngeal carcinoma.In 50% of cases nodal involvement is bilateral. Often cervical lymphadenopathy may be the first presentation) SRB,5th,395.", 'role': 'assistant'}]