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
Deep venous system of brain consists of -a) Internal cerebral veinb) Great cerebral veinc) Basal veinsd) Cavernous sinus 
Select and explain. 
A. abc, B. bc, C. acd, D. bcd
A: abc
Answer: A: abc 
Explanation: Deep veins of the cerebral hemispheres

Internal cerebral veins (two)
Basal veins (two)
Great cerebral vein of GalenQ