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