A Rod with a Diameter Of $2.00 \mathrm{~mm}$ Projects $20.0 \mathrm{~mm}$ Horizontally Outward from a Wall

A rod with a diameter of $2.00 \mathrm{~mm}$ projects $20.0 \mathrm{~mm}$ horizontally outward from a wall. A $2.00 \mathrm{~N}$ coat is hung from the end of the rod and the rod deflects downward by $4.00 \times 10^{-6} \mathrm{~m}$ . The shear stress on the rod is

A) $3.37 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}$ .
B) $2.78 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}$ .
C) $6.37 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}$ .
D) $5.34 \times 10^{5}\mathrm{~N} / \mathrm{m}^{2}$ .
E) $4.73 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}$