HYDRAULICS. The plane surface $AB$ is rectangular in shape, $1\mathrm{.}8$ meters wide and $3$ meters long into the screen. With oil of specific gravity of $0\mathrm{.}84$ on one side, determine the horizontal reaction on the smooth wall at $B$ if the gate hinged at $A$ if the weight of the gate is negligible.

$55\mathrm{.}33$ kN

$101\mathrm{.}4$ kN

$51\mathrm{.}87$ kN

$83\mathrm{.}44$ kN