This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Which of the following metabolic reactions require vitami B12 but not folate? \nSelect and explain. \nA. Conversion of malonic acid to succinic acid, B. Conversion of homocysteine to methionine, C. Conversion of serine to glycine, D. Thymidylate synthesis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (Ref: KDT 6/e p588) Conversion of malonic acid to succinic acid requires vitamin B12 but not folate. This reaction is required for myelin formation and deficiency of B12 is responsible for demyelination.', 'role': 'assistant'}]