Simplify: $\bigg( \large\frac{2}{5}$$x^2 + \frac{7}{9}$$y^2 \bigg)^2-\bigg( \large\frac{2}{5}x^2-\frac{7}{9} $$y^2\bigg)^2$

Question

$\begin{array}{1 1} \frac{56}{45}x^2y^2 \\ \frac{56}{45} xy \\ \frac{56}{45} \\ x^2y^2 \end{array} $