Two sources of sound placed close to each other, are emitting progressive waves given by $y_1 = 4 sin 600 \pi t$ and $y_2 = 5 sin 608 \pi t$

Question

( A ) 8 beats per second with intensity ratio 25 : 16 between waxing and waning
( B ) 8 beats per second with intensity ratio 81 : 1 between waxing and waning
( C ) 4 beats per second with intensity ratio 25 : 16 between waxing and waning
( D ) 4 beats per second with intensity ratio 81 : 1 between waxing and waning