The beginning of the inner ear is marked by the:

A) tympanic membrane.
B) oval window.
C) eustachian tube.
D) inner ear.

Inner Ear

The innermost part of the ear, containing the cochlea, vestibule, and semicircular canals, responsible for hearing and balance.

Tympanic Membrane

A thin membrane that separates the external ear from the middle ear and vibrates in response to sound waves; commonly known as the eardrum.

Oval Window

A membrane-covered opening that leads from the middle ear to the cochlea of the inner ear, transferring vibrations to fluid within the cochlea.