Hydrostatic

$1.$ A concrete wall of rectangular cross section $5$ m high, $2$ m thickness and $1$ m wide is design to retain water to a depth of $4$ m as shown in the figure. Determine the minimum SG of the concrete so the concrete wall will not collapse due to hydrostatic force from the water.

A$.1\mathrm{.}067$

B$.1\mathrm{.}607$

C$.0\mathrm{.}167$

D$.6\mathrm{.}107$