Final Answer
The stirrup sits against the oval window. Thus the correct option is B.
Explanation
The human ear consists of three tiny bones known as the ossicles: the hammer, anvil, and stirrup. The stirrup, also called the stapes, is the smallest bone in the human body and plays a crucial role in the transmission of sound vibrations. Its position within the middle ear is integral to the auditory process.
When sound waves enter the ear, they travel through the ear canal and cause the eardrum, a thin membrane, to vibrate. These vibrations are then transmitted through the ossicles. The stirrup, being the last bone in this chain, connects to the oval window, a membrane-covered opening that leads to the inner ear.
The oval window separates the middle ear from the inner ear's fluid-filled cochlea. As the stirrup presses against the oval window, it creates pressure waves within the fluid of the cochlea. These waves stimulate the tiny hair cells lining the cochlea, converting mechanical vibrations into electrical signals that the brain interprets as sound.
The precise contact of the stirrup against the oval window allows for the efficient transmission and amplification of sound waves. This critical connection ensures that the auditory system can effectively convert external sound stimuli into neural signals that the brain can process, enabling the perception of sound.
Thus the correct option is B.