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: ENT
[{'content': 'In the Nodal "N" staging of laryngeal carcinoma, extranodal invasion is indicated by \nSelect and explain. \nA. N2C, B. N3A, C. N3B, D. N3C', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]