Two point coherent sources of power `P_(0) nad 4P_(0)` emmitting sound of frequency 150 Hz are kept at point A and B respectively. Both sources are in same phase. A detector is kept at point C as showin in figure. The distance of point A and B is r and 4r form detectro respectively. The speed of sound in medium is 300 m/s . Given `P_(0)=64pi` Watt and r=1m. The intensity observed by detector is
A. `25W//m^(2)`
B. `4W//m^(2)`
C. `9W//m^(2)`
D. zero
