This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cranial Nerve Disorders, Subject name: Medicine
[{'content': 'Artery involved in 3rd cranial nerve lesion? \nSelect and explain. \nA. Anterior communicating, B. Posterior communicating, C. Posterior cerebral, D. Anterior cerebral', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Posterior communicatingRef: Harrison 18/e, chapter 275, Principles and practice of emergency neurology Sid M shah and Kevin M Kelly Textbook of ophthalmology vol. 1 by sunitaagarwal', 'role': 'assistant'}]