This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous System, Subject name: Pathology
Which enzyme protects the brain from free radical injury? 
Select and explain. 
A. Myeloperoxidase, B. Superoxide dismutase, C. MAO, D. Hydroxylase
B: Superoxide dismutase
Answer: B: Superoxide dismutase 
Explanation: Ref: Robbin's Pathology, 9th ed. pg. 48, 80* Antioxidant enzymes include glutathione peroxidase, SOD and catalase.* Deficiency of SOF 1 gene may result in motor neuron disorder.