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: Pathology
[{'content': 'The least common site for a berry aneurysm is - \nSelect and explain. \nA. Vertebral artery, B. Basilar artery, C. Junction of anterior cerebral artery and internal carotid artery, D. Posterior cerebral artery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A berry aneurysm\n\nThe further away the aneurysm from the anterior circulation or from the circle of willis , the less common will be its rate of occurance.\nBerry an aneurysm or Saccular aneurysm or Congenital aneurysm is the most frequent type of intracranial aneurysm.\nMost aneurysms occur in the anterior circulation and are found near the branch\xa0points.\nThe most common site is junction between anterior cerebral artery and anterior communication artery (40%).\nNext most common site is internal carotid artery and posterior communicating artery (20%)\n\nLess frequent sites include\xa0-\n\nTop of basilar artery\nJunction of basilar artery and the superior cerebllar artery or anterior inferior cerebellar artery.\nJunction of vertebral artery and posterior inferior cerebellar artery.', 'role': 'assistant'}]