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 one of the following is synthesized from an essential amino acid? \nSelect and explain. \nA. Alanine, B. Glutamate, C. Proline, D. Tyrosine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Tyrosine is formed from phenylalanine.', 'role': 'assistant'}]