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
Ascorbic acid: 
Select and explain. 
A. Is a reducing agent, B. Decrease iron absorption, C. Is harmless in high doses, D. Is required for lysyl oxidase
A: Is a reducing agent
Answer: A: Is a reducing agent 
Explanation: None