Two liquids of densities $\rho_{1}$ and $\rho_{2}$ ($\rho_{2} = 2\rho_{1}$) are filled up behind a square wall of side 10 m as shown in figure. Each liquid has a height of 5 m. The ratio of the forces due to these liquids exerted on upper part MN to that at the lower part NO is (Assume that the liquids are not mixing):\\
(1) $\frac{1}{3}$\\
(2) $\frac{2}{3}$\\
(3) $\frac{1}{2}$\\
(4) $\frac{1}{4}$