This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Radiology
[{'content': 'Marchiafava-Bignami diseaseis characterized by? \nSelect and explain. \nA. Callosal atrophy, B. Cerebellar atrophy, C. Brainstem atrophy, D. Cerebral peduncular atrophy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans AIt is a rare CNS disorder associated with chronic alcoholism or malnutrition. On imaging there is corpus callosal atrophy and demyelination.Sandwich sign and ears of lynx sign maybe seen.', 'role': 'assistant'}]