The right option is; B. They carry neural signals about a sound wave’s frequency to the brain.
The cochlea is the sense organ that converts sound into neural signals that is sent to the brain. The cochlea contains hair cells that are responsible for hearing. The lower part of the hair cells are joined to the basilar membrane. Within the cochlea, sound waves make the basilar membrane to vibrate up and down and to generate nerve impulses. Below the hair cells are the auditory nerve fibers which pass the signals about a sound wave’s frequency to the brain.