This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': "Spontaneously regressing tumours are \nSelect and explain. \nA. Malignant melanoma, B. Neuroblastoma, C. Ewing's sarcoma, D. Wilm's tumour", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tumors with spontaneous regression Neuroblastoma Choriocarcinoma Renal cell carcinoma Malignant melanoma Retinoblastoma Ref : Robbins 9th edition Pgno : 477, 1041, 955, 1339, 1149', 'role': 'assistant'}]