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
"Blood brain barrier" is present at all of the following sites except : 
Select and explain. 
A. Hebenular nucleus, B. Subfornical organ, C. Cerebellum, D. Pontine nucleus
B: Subfornical organ
Answer: B: Subfornical organ 
Explanation: B i.e. Subfornical organ