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: Surgery
[{'content': 'Which one of the following is the most common tumor 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: Ans. is 'b' i.e. Nasopharyngeal carcinoma", 'role': 'assistant'}]