Question

definition
a structure in the cochlea containing hair cells that serve as the receptors for hearing.
semicircular canals
basilar membrane
organ of corti (ee)
matrix

Explanation:

The organ of Corti in the cochlea contains hair - cells that act as receptors for hearing. Semicircular canals are related to balance, basilar membrane is part of the cochlea but not the structure with hair - cell receptors specifically named here, and "Matrix" is not relevant in this context.

Answer:

C. organ of Corti (ee)