The correct option is (b) 2.35 N/m^2 and soil grains is in motion
Best explanation: The average shear stress = Yw. R. S
= 9.81 x 1000 x 0.6 x 1/2500 = 2.35 N/m^2.
This value is more than 0.53 N/m^2, the soil grains will not be stationary and sediment transport and scouring will occur.