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: Anatomy
All of the following structures are derivatives of the the secondary vesicle called diencephalon, EXCEPT: 
Select and explain. 
A. Thalamus, B. Subthalamus, C. Hypothalamus, D. Cerebral aqueduct
D: Cerebral aqueduct
Answer: D: Cerebral aqueduct 
Explanation: The derivatives of diencephalon are subthalamus, thalamus, hypothalamus, epithalamus and third ventricle. Derivatives of secondary vesicles:Telencephalon: cerebral hemispheres, lateral ventriclesMesencephalon: midbrain, cerebral aqueductMetencephalon: pons, cerebellum, upper aspect of fouh ventricleMyelencephalon: lower aspect of fouh ventricle, medulla oblongataRef: Atlas of Neuroradiologic Embryology, Anatomy, and Variants edited by J. Randy Jinkins page 9