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
The following is inhibitory agent in brain and spinal cord: 
Select and explain. 
A. Glycine, B. Glutamine, C. Aspaate, D. NO
A: Glycine
Answer: A: Glycine 
Explanation: Glycine