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': 'Malignant change in lipoma is most common in ? \nSelect and explain. \nA. Thigh, B. Nape of neck, C. Retroperitoneum, D. Back', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Retroperitoneum", 'role': 'assistant'}]