John has played his music loudly for years. Now, in his 20s, he finds he has a continuous ringing in both of his ears. What would John probably be diagnosed with?

a. tinnitus, which is a nerve-based disorder that has no permanent cure

b. conduction-based hearing impairment; however, hearing aids may be able to help

c. damage to the pinna, which can be corrected with surgery

d. Regardless of the disorder, John will ultimately require a cochlear implant.