This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnostic and operative ENT, Subject name: ENT
[{'content': "Austin's classification for ossicular chain defects depends on \nSelect and explain. \nA. Malleus head and stapes footplate, B. Malleus handle and stapes suprastructure, C. Malleus head and stapes suprastructure, D. Malleus head and stapes head", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Austin in 1971 Classified ossicular defects based on malleus handle and stapes suprastructure into- Group A- having malleus and stapes intact and erosion of long process of incus being the most common defect. Group B - with only malleus and absent stapes. Group C - with only stapes and absent malleus. Group D - with absent malleus and stapes suprastructure. Ref- Glasscock-Shambaugh surgery of the ear, 5tg edition, PG 463-485.', 'role': 'assistant'}]