The specialized hearing receptors found in the cochlea are cells.

epithelial
hair
skin
salivary gland

The correct answer is hair cells.

Explanation:

Sensory organs accountable for hearing and balance is present in the inner ear. The cochlea is a bony snail-shaped structure that is the hearing part of the inner ear.  

The cochlea has two fluids, sensory receptor, and the Organ of Corti, that contains hair cells, also known as nerve receptors for hearing.

The bones of the middle ear transform sound into a force that pushes the membrane that moves the fluid in the cochlea and stimulates the tiny hair cells. Hair cells transfer the nerve impulses to the cochlear nucleus, then the nerve impulses are taken to the auditory cortex of the brain.

Thus, the correct answer is hair.