**Core Concept**
Scheibe's dysplasia is a type of congenital inner ear malformation characterized by a defective formation of the otocyst, leading to a non-functioning inner ear. This results in sensorineural hearing loss, often bilateral and profound.

**Why the Correct Answer is Right**
Scheibe's dysplasia, also known as cochlear dysplasia, involves a failure of the otocyst to develop into a normal cochlear structure. This leads to a non-functional cochlea, which in turn causes sensorineural hearing loss. The cochlea is responsible for converting sound vibrations into electrical signals that are transmitted to the brain for processing. In Scheibe's dysplasia, the abnormal development of the cochlear structures impairs this process, resulting in hearing loss.

**Why Each Wrong Option is Incorrect**
**Option A:** Michel aplasia refers to the absence of the cochlear duct, which is a different type of congenital inner ear malformation.
**Option B:** Mondini's dysplasia is characterized by a partial or complete absence of the cochlear duct and a malformed cochlear structure, but it is not the most common congenital dysplasia of the ear.
**Option C:** Alexander's dysplasia, also known as the "enlarged vestibular aqueduct syndrome," involves an abnormal development of the vestibular system, but it is not the most common congenital dysplasia of the ear.

**Clinical Pearl / High-Yield Fact**
Scheibe's dysplasia is often associated with other congenital anomalies, such as microtia or other inner ear malformations, and may be identified on prenatal ultrasound or postnatally through audiological evaluation.

**✓ Correct Answer: D. Scheibe's dysplasia**