 The young are not listening to their elders, and perhaps they never have. But now it happens that, with many of them, the reason may be medical. The young aren’t listening because they can’t hear. Just as nagging parents have long suspected, otologists (hearing specialist) now report that youngsters are going deaf as a result of blasting their eardrums with electronically amplified rock ‘n’ roll.
  The hearing specialists used to worry about loud noise as a cause of deafness only in industrial and military situations. They knew that eight hours of daily exposure, year in and year out, to the din of the proverbial boiler factory, would eventually result in permanent hearing loss. Riveters were particularly susceptible. Then they learned that the same thing happened to aviators. After the advent of jets, the hazard applied to the ground crews at airport and flight-deck personnel aboard aircrafts – hence the introduction of insulated noise absorbing plastic earmuffs.
  In discotheques and rock ‘n’ roll joints, the trouble is not so much in the instrument themselves, or the close quarters. The blame goes to the electronic amplifiers. An old-fashion military ban, playing a march in Ramat Park, generated as much sound. But the sound was not amplified and was dissipated in the open air. A trombonist sitting in front of a tuba player might be a bit deaf for an hour or so after a concert, and then his hearing returns to normal. A microphone hooked up to a public address system did not appreciably increase the hearing hazard. What he did was multiple microphones and speakers, and the installation of internal microphones in such instruments as guitars and bouzoukis.
‘The same thing happened to aviators’. This excerpt according to the passage, means
-
A.
that riveters were particularly susceptible -
B.
industrial and military deafness -
C.
that continued loud noise resulted in deafness -
D.
that working in a boiler factory affected one’s hearing