This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
Which of the following acts as coenzyme, not as co-factor? 
Select and explain. 
A. Ascorbic acid, B. Biotin, C. Thiamine, D. Folic acid
A: Ascorbic acid
Answer: A: Ascorbic acid 
Explanation: None