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': 'Vitamin B12 deficiency can lead to all, except: \nSelect and explain. \nA. Megaloblastic aneamia., B. Myopathy, C. Optic neuritis, D. Myelopathy.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vitamin B12 deficiency\nA. Hematological manifestations\n\nMegaloblastic anemia\nMacrocytic anemia\n\nB. Neurological\n\nCerebrum —> dementia\nSpinal cord --> myelopathy\nCranial nerve —> optic neuritis\nPeripheral nerve —> Peripheral neuropathy', 'role': 'assistant'}]