Consider a retaining wall with a simple rectangular cross$-$section $(0\mathrm{.}8$m x $3$m$).$ Thebackfill soils $($gamma $=19$ kN$/$m$3,$ phi' $=30$ degrees, c$\text{'}=0$ kPa$)$ are sloped at alpha $=10$ degrees. The wall has no embedment. The soil$-$wall friction angle is $0\mathrm{.}5*$phi$.$ Using Coulomb theory, determine the magnitude of the active thrust on the wall due to the backfill soils. Choose one option $30\mathrm{.}12$ kN$/$m

$28\mathrm{.}47$ kN$/$m

$29\mathrm{.}34$ kN$/$m

$26\mathrm{.}54$ kN$/$m