The Frequency Theory of Pitch Makes Good Sense, but It

The frequency theory of pitch makes good sense, but it has a major problem. What is this problem?

A) Cells in the organ of Corti do not vibrate.
B) Frequencies do not penetrate to the cochlea.
C) The basilar membrane can only respond to sounds above 50 db.
D) Sensory neurons in the inner ear cannot fire faster than 1000 cycles per second.
E) Pitch is not really related to frequency.