This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thalamus, Hypothalamus and Basal Ganglia, Subject name: Physiology
[{'content': 'Not a part of basal ganglia is? \nSelect and explain. \nA. Caudate nucleus, B. Corpus striatum, C. Lenticular nucleus, D. Sub-Fornical organ', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) Sub-fornical Organ* The subfornical organ (SFO), situated on the ventral surface of the fornix (the reasoning behind the organs name), at the interventricular foramina (foramina of Monroe), is one of the circumventricular organs of the brain, meaning that it is highly vascularized and does not have a blood-brain barrier, unlike the vast majority of regions in the brain.* The SFO is a sensory circumventricular organ responsive to a wide variety of hormones and neurotransmitters, as opposed to a secretory circumventricular organ.', 'role': 'assistant'}]