This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gallbladder, Subject name: Surgery
[{'content': 'According to 8th AJCC TNM classification of carcinoma Gallbladder, minimum number of LN involved in N2? \nSelect and explain. \nA. 3, B. 4, C. 5, D. 6', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 8th AJCC (2017) TNM classification of Ca. gall bladder N1 - Metastasis to 1 - 3 regional nodes. N2 - Metastasis to 4 or more regional nodes. M1 - Distant metastasis.', 'role': 'assistant'}]