Why Are We Able to Perceive the Pitch of a Sound

Why are we able to perceive the pitch of a sound?

A) The hammer, anvil, and stirrup vibrate at different speeds.
B) Different parts of the basilar membrane vibrate in response to different frequencies of sound.
C) Different parts of the tectorial membrane vibrate at different sound frequencies.
D) The basilar membrane is stiff and narrow at the end away from the oval window.
E) The tympanum vibrates more strongly at high pitches.