This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demyelinating disorder, Subject name: Medicine
[{'content': 'A 9-year-old boy is diagnosed with multiple sclerosis (MS). Which of the following nervous structures would most likely be affected by this disease? \nSelect and explain. \nA. Trigeminal ganglion, B. Superior cervical ganglion, C. Optic nerve, D. Facial nerve', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Multiple sclerosis affects only axons in CNS (spinal cord and brain) that have myelin sheaths formed by oligodendrocytes. Optic nerve is considered to be pa of CNS, as it is derived from an outpouching of diencephalon. All other nervous structures are in the PNS and have their myelin sheaths formed by Schwan cells', 'role': 'assistant'}]