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': "'Alien limb' is characteristically seen in: \nSelect and explain. \nA. Coico basal degeneration, B. Diffuse Lewy body disease, C. Fronto temporal dementia, D. Alzheimer's disease", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Coicobasal degeneration (CBD) is a slowly progressive dementing illness associated with severe gliosis and neuronal loss in both the coex and basal ganglia. CBD with unilateral onset presents with rigidity, dystonia, and apraxia of one arm and hand, sometimes called the alien limb when it begins to exhibit unintended motor actions. Ref: Harrisons principles of internal medicine, 18th edition, Page: 3312.', 'role': 'assistant'}]