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': 'A patient had 3 cm mass over the lower lip and a single lymph node measuring 3 cm was present on contralateral side. TNM staging of this lip carcinoma will be: \nSelect and explain. \nA. T1 N2a, B. T2 N2b, C. T2 N2c, D. T1 N2b', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Tis: Carcinoma in insites.\nT1: Tumor <2 cm.\nT2: 2-4 cm.\nT3: > 4 cm.\nN1: Single ipsilateral Lymph node < 3 cm.\nN2a: Single ipsilateral Lymph node > 3 cm but < 6 cm.\nN2b: Multiple ipsilateral Lymph node of size < 6 cm.\nN2c: Bilateral or contralateral Lymph node of size < 6 cm.\nN3: Any Lymph node of size > 6 cm or pericapsular invasion.', 'role': 'assistant'}]