This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
[{'content': 'In vitamin B12 deficiency, folate is trapped in the form of \nSelect and explain. \nA. Formyl THFA, B. Methenyl THFA, C. Methyl-THFA, D. Methylene-THFA', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Methylation of homocysteine to methionine is the only way of regeneration of active THFA from methyl THFA. Methionine synthase reaction requires methyl cobalamin. So, deficiency of methyl-B12 leads to trapping of THFA in less utilised methyl-THFA - phenomenon known as folate trap.', 'role': 'assistant'}]