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 of the following are unpaired vessel in CNS : 
Select and explain. 
A. Anterior-cerebral aery, B. Basilar aery, C. Posterior-cerebellar aery, D. Posterior-communicating aery
B: Basilar aery
Answer: B: Basilar aery 
Explanation: B i.e. Basilar aery