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': 'Acute disseminated encephalomyelitis (ADEM) is a white matter disease that is indistinguishable from multiple sclerosis by all except \nSelect and explain. \nA. Monophasic, B. Rapidly lethal, C. Associated with brainstem and spinal cord disease, D. Associated with MRI  lesions which may resolve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ADEM is a demyelinating disease of the brain ,brainstem and spinal cord that is indistinguishable from MS on MRI. However,it is monophasic,\xa0 that is\xa0 it occurs acutely on a single occasion and not in a recurrent fashion like MS.', 'role': 'assistant'}]