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': 'Opsomyoclonus is encountered as C/F of - \nSelect and explain. \nA. Meningioma, B. Neuroblastoma, C. Neurofibromatosis, D. Excision', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "At least 50% of children with opsoclonus-myoclonus have an underlying neuroblastoma." - Harrison\nOpsoclonus-Myoclonus Syndrome \n\nOpsoclonus is a disorder of eye movement characterized by involuntary, chaotic saccades that occur in all directions of gaze; it is frequently associated with myoclonus and ataxia.\n\nCauses of Opsoclonus-myoclonus \n\nIdiopathic\nCancer-related (paraneoplastic)\n\n\nCancers associated with opsoclonus-myoclonus are usually lung and breast cancers in adults and neuroblastoma in children.', 'role': 'assistant'}]