When audiometry is used to test a driver's hearing:
a. The driver passes if there is no greater than 40dB average loss over 500,
1000 and 2000 Hz in the better ear.
b. The driver passes if there is no greater than 40dB average loss over 500,
1000 and 2000 Hz in the better ear. If hearing aids are worn, both ears must
pass.
c. The driver passes if there is no greater than 40dB average loss over 2000,
3000 and 4000 Hz in the better ear.
d. The driver passes if there is no greater than 40dB average loss over 500,
1000 and 2000 Hz in both ears.