This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Childhood tumors, Subject name: Pediatrics
[{'content': 'The International Neuroblastoma Staging System (INSS) stage 4S includes metastasis to all the following except \nSelect and explain. \nA. Liver, B. Skin, C. Bone marrow, D. Bone', 'role': 'user'}, {'content': 'Answer: D \nExplanation: INSS stage 4S refers to neuroblastoma in children younger than 1 yr of age with dissemination to liver, skin, and/or bone marrow without bone involvement and with a primary tumor that would otherwise be staged as INSS stage 1 or 2. Reference: Nelson; Neuroblastoma; Page no: 2463', 'role': 'assistant'}]