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
The proxidant action of Vitamin C is potentiated by: 
Select and explain. 
A. Selenium, B. Copper, C. Calcium, D. Iron
B: Copper
Answer: B: Copper 
Explanation: Ans. B. Copper(Ref: Harper 31/e page 533-540)Ascorbate is antioxidant, but it can be a source of hydroxyl radical by reacting with Cu2+ ions. Antioxidant vitamins that can act as prooxidants are:Beta caroteneAscorbateTocopherol