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
[{'content': 'Which of the following is not a derivative of amino acid tyrosine \nSelect and explain. \nA. Thyroxine, B. Melatonin, C. Melanin, D. Epinephrine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Melatonin and serotonin are derivatives of Tryptophan.', 'role': 'assistant'}]