This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Meninges & Blood Vessels of the Brain, Subject name: Anatomy
Which area is out of the blood brain barrier 
Select and explain. 
A. Thalmus, B. Cerebral cortex, C. IV ventricle, D. Area postrema
D: Area postrema
Answer: D: Area postrema 
Explanation: Ans. is 'd' i.e. Area Postrema There are four areas which lie outside the blood brain barrier : these areArea postremaOrganum vasculosum of the lamina terminalis (OVLT)Subfornical organ (SFO)The posterior pituitary (neurohypophysis) and the adjacent ventral part of the median eminence of the hypothalamus.These areas are also called as circumventricular organs.