A point source emits sound waves with an average power out-put of 8.0 w .Then find intensity at 3.0 m & distance at which the sound level is 40 dB

Question

$(a)\;0.707\;w/m^2\;,2.52\times10^{5} \;m\qquad(b)\;0.707\;w/m^2\;,2.52\times10^{3} \;m\qquad(c)\;0.707\;w/m^2\;,2.52\times10^{4} \;m\qquad(d)\;None$