This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Which of the following structures is not at immediate risk of erosion by cholesteatoma ? 
Select and explain. 
A. Long process of incus, B. Fallopian canal containing facial nerve, C. Horizontal/ lateral semicircular canal, D. Base plate of stapes
D: Base plate of stapes
Answer: D: Base plate of stapes 
Explanation: Ans. is 'd' i.e., Base plate of stapes Cholesteatoma has the propey to destroy the bone by viue of the enzymes released by it. Structures immediately at the risk of erosion are : - Long process of incus. Fallopian canal containing facial nerve. Horizontal / lateral semicircular canal