$\begin{array}{1 1}(A)\;\large\frac{\pi Yrd^2}{2l}\\(B)\;\large\frac{\pi Yr^2d^2}{l^2}\\(C)\;\large\frac{\pi Yr^2d^2}{2l^2}\\(D)\;\large\frac{\pi Yr^2d^2}{4l^2}\end{array} $