When the Volume Control on a Stereo System Is Increased

When the volume control on a stereo system is increased, the voltage across a loudspeaker changes from V ₁ to V ₂ , and the decibel increase is given by Find the decibel increase if the voltage changes from 1.6 volts to 3.9 volts.

A) db = 13.0
B) db = 11.6
C) db = 21.4
D) db = 9.3
E) db = 8.2