This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
Gamma glutamate carboxypeptidase is linked with absorption of 
Select and explain. 
A. Riboflavin, B. Niacin, C. Folic acid, D. Pyridoxine
C: Folic acid
Answer: C: Folic acid 
Explanation: Function in the brain GCPII directly cleaves NAAG into NAA and glutamate. NAAG has been shown, in high concentration, to indirectly inhibit the release of neutrotransmitters, such as GABA and glutamate. It does this through interaction with and activation of presynaptic group II mGluRs Ref: guyton and hall textbook of medical physiology 12 edition