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: ENT
[{'content': 'Which of the following is included in the Levenson criteria for congenital cholesteatoma \nSelect and explain. \nA. White mass medial to normal tympanic membrane, B. Attico-antral perforation of the tympanic membrane, C. Definite history of otorrhoea, D. History of prior otologic procedures', 'role': 'user'}, {'content': "Answer: A \nExplanation: levenson's criteria : Mass medial to the tympanic membrane. Normal tympanic membrane. No previous history of ear discharge, perforation or ear surgery. Ref: Internet sources.", 'role': 'assistant'}]