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
Floor of body of lateral ventricle is formed by 
Select and explain. 
A. Septum pellucidum, B. Rostrum of corpus callosum, C. Thalamostriate  vein, D. Genu of corpus callosum
C: Thalamostriate  vein
Answer: C: Thalamostriate  vein 
Explanation: Floor of body of lateral ventricle is formed by 

Caudate nucleus
Thalamostriate vein
Thalamus upper  surface 
Body of fornix upper surface

Rostrum of corpus callosum forms floor, septum pellucidum forms medial wall, and genu of corpus callosum forms anterior wall of anterior horn of lateral ventricle.