The correct choice is (d) Shear stress is non zero along the line of symmetry

Easiest explanation: In general, the primary variables are obtained using FEM and secondary variables are calculated using the primary variables. In the viscous ﬂow, both the velocity components are zero on ﬁxed walls, and shear stress is zero along the line of symmetry. Vertical velocity component vy and horizontal stress tx must be zero along the horizontal line of symmetry and vx, ty must be zero along the vertical line of symmetry.