A Glass Window Is Installed in the Window Space and the Intensity

A glass window is installed in the window space and the intensity level of the sound entering through the window is reduced from 72 dB to 47 dB.The factor,by which the acoustic power entering the chamber is reduced by the glass window,is closest to:

A) 3.2 × 10^-3
B) 2.2 × 10^-2
C) 5.6 × 10^-2
D) 1.0 × 10^-1
E) 1.5 × 10^-1