Based on the logarithmic scale discussed in the first paragraph, how many times can a shotgun blast be more powerful than rock music

A．people will generally improve their hearing
B．people will have worse hearing
C．people will wear contact lenses and hearing aids as well
D．people wearing hearing aids will outnumber those wearing contact lenses

A．his tight ear has been damaged
B．his nerve system is inefficient
C．there is some problem with his brain
D．some of the delicate hairs in his inner ear have suffered a great damage