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
GABA is produced from: 
Select and explain. 
A. Alanine, B. Glycine, C. Glutamate, D. Glutamine
C: Glutamate
Answer: C: Glutamate 
Explanation: Glutamate