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
Mechanism of analgesia is by: 
Select and explain. 
A. Nociceptin stimulation, B. Nocistatin stimulation, C. O.L.R.I, D. All
B: Nocistatin stimulation
Answer: B: Nocistatin stimulation 
Explanation: B i.e. Nocistatin stimulation