Research Has Found That,since the Introduction of the 'Ear Bud

Multiple Choice

Research has found that,since the introduction of the 'ear bud" earphone,the hearing ability of the average 21-year old of today is equivalent to the average 80-year old of ten years ago.This suggests that the "ear bud" might be causing

A) conduction deafness.
B) obstructive deafness.
C) amplitude deafness.
D) nerve deafness.