Consider a retaining wall with a simple rectangular cross$-$section $(0\mathrm{.}8$m x$3$m$).$ The backfill soils $($gamma $=19$ kN$/$m$3,$ phi' $=30$ degrees, c$\text{'}=0$ kPa$)$ are sloped atalpha $=10$ degrees. The wall has no embedment. The soil$-$wall friction angle is$0\mathrm{.}5*$phi$.$ Using Coulomb theory, determine the location$/$angle of the active thrust on the wall due to the backfill soils. Chooee one option & give explnation $1$m from base of wall, $15$ degree angle with horizontal $2$m from base of wall, $0$ degree angle with horizontal $1$m from base of wall, $0$ degree angle with horizontal $2$m from base of wall, $15$ degree angle with horizontal