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
Cochlear basal turn dysplasia is known as 
Select and explain. 
A. Michel dysplasia, B. Scheibe dysplasia, C. Alexander dysplasia, D. Bing Schiebenmann dysplasia
C: Alexander dysplasia
Answer: C: Alexander dysplasia 
Explanation: Congenital malformations of the inner ear Complete labyrinthine aplasia (Michel), Complete membranous labyrinthine dysplasia (Siebenmann-Bing), Cochleosaccular dysplasia (Scheibe), Cochlear basal turn dysplasia (Alexander) Alexander dysplasia : It affects only the basal turn of membranous cochlea. Thus only high frequencies are affected. Residual hearing is present in low frequencies and can be exploited by amplification with hearing aids. Ref : Diseases of ENT by Dhingra 6th edition Pgno : 115