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
Vitamin B12 acts as a coenzyme to which one of the following enzymes? 
Select and explain. 
A. Isocitrate dehydrogenase, B. Homocysteine methyl transferase, C. Glycogen synthase, D. G-6-P dehydrogenase
B: Homocysteine methyl transferase
Answer: B: Homocysteine methyl transferase 
Explanation: None