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': 'Group of lymph node involved in breast carcinoma are all of the following except: March 2005 \nSelect and explain. \nA. Supraclavicular, B. Pretracheal, C. Axillary, D. Internal mammary', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Pretracheal Lymphatic metastasis occurs primarily to the axillary and the internal mammary lymph nodes. Tumours in the posterior one-third of the breast are more likely to drain into the internal mammary lymph nodes. Involvement of supraclavicular nodes and any of the contralateral lymph nodes represent advance disease.', 'role': 'assistant'}]