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
[{'content': 'Which of the following acts as coenzyme, not as co-factor? \nSelect and explain. \nA. Ascorbic acid, B. Biotin, C. Thiamine, D. Folic acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]