This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: vitamins, Subject name: Biochemistry
A vitamin related to a co-factor in glycine metabolism is 
Select and explain. 
A. Thiamine, B. Biotin, C. Folic acid, D. Pantothenic acid
C: Folic acid
Answer: C: Folic acid 
Explanation: Reference: Harpers illustrated biochemistry 30th edition