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
In which of the following head and neck cancers, is lymph node metastasis least common? 
Select and explain. 
A. Tongue, B. Buccal mucosa, C. Hard palate, D. Lower alveolus
C: Hard palate
Answer: C: Hard palate 
Explanation: LN metastasis is most common in CA tongue > Floor of mouth > Lower alveolus > Buccal mucosa > Upper alveolus > Hard palate > Lip