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
Posterior communicating aery is a branch of ? 
Select and explain. 
A. Internal carotid, B. External carotid, C. Middle cerebral, D. Posterior superior cerebellar
A: Internal carotid
Answer: A: Internal carotid 
Explanation: Posterior communicating aery is a branch of the cerebral pa of the internal carotid aery. The cerebral pa lies at the base of the brain.