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': 'Gamma-aminobutyrate is synthesized from? \nSelect and explain. \nA. Fumarate, B. Glutamate, C. Histidine, D. Glycine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gamma-aminobutyric acid (GABA) is formed by decarboxylation of L-glutamate.', 'role': 'assistant'}]