This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition & Digestion, Subject name: Biochemistry
Selenium is a cofactor in the following enzyme: 
Select and explain. 
A. Glutathione peroxidase, B. Cytochrome oxidase, C. Cytochrome reductase, D. Xanthine oxidase
A: Glutathione peroxidase
Answer: A: Glutathione peroxidase 
Explanation: Ans. A. Glutathione peroxidase(Ref: Harper 31/e page 534)SeleniumCofactors for* Glutathione peroxidase* Deiodinase* Thioredoxin reductase* Antioxidant along with vitamin E