A Bingham fluid of viscosity u = 10 Pa-s, and yields stress T, = 10 kPa, is sheared between flat parallel plates separated by a distance 10-3 m/s. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is (a) 10 kPa (b) 20 kPa (c) 30 kPa (d) 40 kPa