From a point on the group at a distance 2 meters from the foot of a vertical wall , a ball is thrown at an angle $45^{\circ}$ which just clear the top of the wall and afterwards strikes the ground at a distance 4 m on the other side. The height of the wall is

Question

$\begin{array}{1 1}(A)\; \frac{1}{3} \;m\\(B)\;\frac{2}{3}\;m \\(C)\;\frac{3}{4} \;m\\(D)\;\frac{4}{3}\;m \end{array}$