Final answer:
d. coarse
The basic hair textures are fine, medium, and coarse. Hair cells near the base of the basilar membrane respond best to high-frequency sounds due to its stiff and narrow structure, making it more sensitive to such vibrations.
Step-by-step explanation:
The basic hair textures are fine, medium, and coarse. So the correct answer is d. coarse. When it comes to the basilar membrane located in the cochlea of the inner ear, hair cells near the base respond best to high-frequency sounds. This is because the base of the basilar membrane is stiffer and narrower, which makes it more responsive to these higher frequency vibrations.