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: Biochemistry
All are antioxidant except ? 
Select and explain. 
A. Vitamin A, B. Catalase, C. Cystein, D. Glutamine
D: Glutamine
Answer: D: Glutamine 
Explanation: Ans. is 'd' i.e., Glutamine