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': 'Corticobasal degeneration is characterized by all except \nSelect and explain. \nA. Frontoparietal cortical atrophy, B. Symmetric, C. Late onset, D. Limb apraxia', 'role': 'user'}, {'content': "Answer: B \nExplanation: Corticobasal degeneration is atypical parkinson's disease. Atypical parkinson's disease is generally symmetric in nature except for corticobasal degeneration.", 'role': 'assistant'}]