The answer is cochlea and auditory.
The cochlea located in the inner ear, translates sound vibrations into an impulse for the auditory nerve.
The ear, the hearing organ, has three parts:
1. the outer ear - it consists of the pinna, the ear canal, and tympanic membrane.
2. the middle ear - it consists of the tympanic cavity and three ossicles (hammer, anvil, and stirrup).
3. the inner ear - it consists of the semicircular canals, the utricle and saccule, and the cochlea.
Regarding other choices:
1. Auditory nerve transmits auditory information to the central nervous system.
2. Olfactory nerve transmits olfactory information to the central nervous system.
3. Optic nerve transmits visual information to the central nervous system.