Choices C and E are correct. Conductive hearing loss is typically reversible and caused by cerumen, foreign body, tumor, edema, and acute infection.

Choices A, B, and D are incorrect. Presbycusis, prolonged exposure to noise, and ototoxic substances cause sensorineural hearing loss. Sensorineural hearing loss is often irreversible.

Hearing loss is classified into three types: conductive, sensorineural, and mixed.

• Conductive hearing loss is caused by an obstruction to the sound transmission within the ear. Causes of this type of hearing loss include cerumen, foreign body, water, edema, infection (otitis media), or tumor. This type of hearing loss may be reversible.
• Sensorineural hearing loss is caused by damaged hair cells within the inner ear or the impairment of the vestibulocochlear nerve. Causes of this type of hearing loss include prolonged exposure to noise, ototoxic substances (aminoglycosides), diabetes mellitus, and presbycusis (age-related hearing loss). This type of hearing loss is often not reversible.
• Mixed hearing loss has both conductive and sensorineural components. Causes include head trauma, genetic disorders, and infections.