The figure shows a vertical retaining wall with backfill consisting of cohesive-frictional soil and a failure plane developed due to passive earth pressure. The forces acting on the failure wedge are: \(P\) as the reaction force between the wall and the soil, \(R\) as the reaction force on the failure plane, \(C\) as the cohesive force along the failure plane and \(W\) as the weight of the failure wedge. Assuming that there is no adhesion between the wall and the wedge, identify the most appropriate force polygon for the wedge.
