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
Which is the least common site for the occurance of berry aneurysm? 
Select and explain. 
A. Anterior communicating aery, B. Middle cerebral aery, C. Veebral aery, D. Basilar aery
C: Veebral aery
Answer: C: Veebral aery 
Explanation: 85% of berry aneurysms occur in the anterior circulation, mostly on the Circle of Willis. 3 most common anterior locations are over : anterior communicating aery, posterior communicating aery and middle cerebral aery. 10% of it occur over basilar aery and only 5% occur on veebral aery. Reference: Handbook of Neurosurgery By Mark Greenbergpage 1055.