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': "In children persistent priapism may result due to \nSelect and explain. \nA. Thrombosis of venous plexus, B. Leukaemia, C. Wilm's tumour, D. Trauma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]