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': 'The most common site of lymphangiosarcoma is \nSelect and explain. \nA. Liver, B. Spleen, C. Post mastectomy edema of arm, D. Retroperitoenum', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lymphangiosarcoma is a rare tumor that develops as a complication of long-standing (usually more than 10 years lymphedema.', 'role': 'assistant'}]