This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: Anatomy
[{'content': "Vertical crest in fundus of the internal auditory canal is known as: \nSelect and explain. \nA. Bill's bar, B. Ponticulus, C. c, Cog, D. Falciform crest", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. Bill\'s bar Vertical crest in fundus of the internal auditory canal is known as Bill\'s bar."Vertical crest in fundus of internal auditory canal is known as Bill\'s-barand it is used as a surgical landmark for facial nerve identification. Grays 40/e p636', 'role': 'assistant'}]