Frequency theory proposes that:

A) pitch is determined by the location on the basilar membrane where the message originated.
B) pitch is determined by the quality of the sound wave.
C) the frequency of the vibrations of the basilar membrane is translated into an equivalent frequency of nerve impulses.
D) nerve cells fire in sequence, not individually.

Frequency theory proposes that the frequency of vibrations of the basilar membrane is translated into an equivalent frequency of nerve impulses, suggesting that pitch perception is related to the firing rate of auditory neurons. Choice A describes place theory, not frequency theory. Choice B is incorrect because sound quality rather than pitch is influenced by sound wave characteristics. Choice D is incorrect because frequency theory suggests that nerve cells do fire individually based on the frequency of the sound wave.