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': "True about primary lymphedema:\na) Prevalence is 2%\nb) Onset b/w 2-35 years indicates lymphedema tarda\nc) Onset >35 yrs indicates praecox type \nd) Associated with Milroy's disease \ne) Lymphangiosarcoma may occur \nSelect and explain. \nA. abde, B. de, C. bde, D. bcde", 'role': 'user'}, {'content': 'Answer: B \nExplanation: "The primary lyrnphedemas are relatively uncommon, occurring in 1 of every 10,000 individuals"-Sabiston\n"Lymphangiosarcoma is a rare tumor that develops as a complication of long-standing (usually more than 10 years) lymphedema."- Sabiston\n"Cutaneous lymphangiosarcoma may develop in chronically lymphedematous extremities."- Devita 8/e Chapter 45', 'role': 'assistant'}]