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: Medicine
[{'content': "Which of the following is the Post - Chemotherapy based staging system in Wilm's tumor: \nSelect and explain. \nA. National Wilm's Tumor staging System (NWTSG), B. National Wilm's Tumor staging System (NWTSG), C. AJCC TNM, D. Chadwick", 'role': 'user'}, {'content': "Answer: B \nExplanation: Answer is B (International Society of Pediatric Oncology-STOP) : The post-chemotherapy based staging system is the `SLOP' staging system developed by the International society of pediatric oncology.", 'role': 'assistant'}]