$A$ container of large uniform cross-sectional area $A$ is resting on a horizontal surface and holds two immiscible,non-viscous,and incompressible liquids of densities $d$ and $2d$,each of height $\frac{H}{2}$,as shown. The upper surface of the liquid with lower density is open to the atmosphere. $A$ small hole is made on the wall of the container at height $h$ $(h < \frac{H}{2})$. The initial speed of efflux of the liquid at the hole is:

• A
  $\left( {3H - 4h} \right)g$
• B
  $\frac{{\left( {3H - 4h} \right)g}}{2}$
• C
  $\sqrt {\left( {3H - 4h} \right)g} $
• D
  $\sqrt {\frac{{\left( {3H - 4h} \right)g}}{2}} $