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
[{'content': 'The cofactor involved in sulphur containing amino acid metabolism is which of the following? \nSelect and explain. \nA. Folic acid, B. Biotin, C. Vitamin B1, D. Vitamin B12', 'role': 'user'}, {'content': 'Answer: D \nExplanation: While both folic acid and vitamin B12 are involved in sulphur containing amino acid metabolism, vitamin B12 acts as cofactor and folate acts as substrate.', 'role': 'assistant'}]