Two wires are fixed in a sonometer. Their tensions are in the ratio 8:1. The lengths are in the ratio 36:35. The diameter are in the ratio 4:1 Densities of the materials are in the ratio 1:2 If the lower frequency in the setting is 360 Hz. The beat frequency when the two wires are sounded together is
A. 5
B. 8
C. 6
D. 10