A wire of $9.8\times {10}^{-3} {\mathrm{kgm}}^{-1}$ passes over a frictionless light pulley fixed on the top of a frictionless inclined plane which makes an angle of 30° with the horizontal. Masses m and M are tied at the two ends of wire such that m rests on the plane and M hangs freely vertically downwards. The entire system is in equilibrium and a transverse wave propagates along the wire with a velocity of 100 ms^–1. Choose the correct option

• A

  m = 20 kg

• B

  m = 5 kg

• C

  m = 2 kg

• D

  m = 7 kg