Cavity of mesencephalon: (A) Lateral ventricle, (B) Fouh ventricle, (C) Cerebral acqueduct, (D) Third ventricle
Answer is C. The cavity of mesencephalon forms the cerebral aqueduct.The cavity of Rhombencephalon forms the fouh ventricle.The cavity of prosencephalon forms lateral and third ventricle.(Ref: Vishram Singh textbook of clinical neuroanatomy second edition pg 4)