This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brain , Subject name: Anatomy
Floor of third ventricle is formed by all except 
Select and explain. 
A. Tuber cinereum, B. Posterior perforated substance, C. Tegmentum, D. Anterior pituitary
D: Anterior pituitary
Answer: D: Anterior pituitary 
Explanation: The floor is formed from before backwards by:Optic chiasmTuber cinereumInfundibulumMamillary bodiesPosterior perforated substanceTegmentum of midbrain(Ref: Vishram Singh textbook of clinical neuroanatomy second edition pg 137)