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': 'Margins of squamous cells carcinoma is - \nSelect and explain. \nA. Inverted, B. Everted, C. Rolled, D. Undermined', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]