This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'Scutum is present in \nSelect and explain. \nA. Roof, B. Lateral wall, C. Anterior wall, D. Posterior wall', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The scutum in the ear is a sharp bony spur formed by the superior wall of the external auditory canal and the lateral wall of the tympanic cavity. REF.BDC VOL.3,SIXTH EDITION', 'role': 'assistant'}]