Users who call from a Cisco IP Phone to external PBX phones report an echo while their call has sufficient loudness.
Which solution most directly reduces this caller echo?
A. Change the input gain from -3 to -6.
B. Change the input gain from -3 to -1.
C. Change the output attenuation from 5 to 1.
D. Change the output attenuation from 5 to 1 and change the input gain from -3 to -1.
