This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, Subject name: Surgery
[{'content': 'In which of the following head and neck cancers, is lymph node metastasis least common? \nSelect and explain. \nA. Tongue, B. Buccal mucosa, C. Hard palate, D. Lower alveolus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: LN metastasis is most common in CA tongue > Floor of mouth > Lower alveolus > Buccal mucosa > Upper alveolus > Hard palate > Lip', 'role': 'assistant'}]