This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzymes, Subject name: Biochemistry
Which of the following is a selenium-dependent enzyme? 
Select and explain. 
A. Glucokinase, B. Aminotrasnferase, C. Glutathione peroxidase, D. Lysyl hydroxylase
C: Glutathione peroxidase
Answer: C: Glutathione peroxidase 
Explanation: Selenium is a trace element nutrient that functions as a cofactor for glutathione peroxidases and ceain forms of thioredoxin reductase.