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': "'N3' in Head & Neck cancer TNM staging refers to \nSelect and explain. \nA. Ipsilateral lymph node 3-6 cm, B. Contralateral lymph node 3-6 cm, C. Bilateral lymph nodes 3-6 cm, D. Contralateral lymph node > 6 cm", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Answer- D. Contralateral lymph node > 6 cmN3- Metastasis in a lymph node > 6 cm in greatest dimension', 'role': 'assistant'}]