This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Biochemistry
[{'content': 'Epinephrine is synthesized from norepinephrine by \nSelect and explain. \nA. Hydroxylation, B. N-methylation, C. Deamination, D. Carboxylation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Norepinephrine can be conveed into epinephrine by the enzyme phenylethanolamine N-methyltransferase with S-adenosyl-L-methionine as cofactor.', 'role': 'assistant'}]