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: Physiology
[{'content': 'Epinephrine is most closely related in structure to: \nSelect and explain. \nA. Niacin, B. Tyrosine, C. Methionine, D. Glycerol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]