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: Medicine
Stimulation of which of the following areas of brain is experimentally used to control intractable pain - 
Select and explain. 
A. Periaqueductal grey matter, B. Mesencephalon, C. Subthalmic nucleus, D. Medical fore brain bundle
A: Periaqueductal grey matter
Answer: A: Periaqueductal grey matter 
Explanation: None