Where is the maximum stress in the concrete located?

Cross-sectional sketch with a rectangular "Concrete" block fixed against a hatched wall at far left. A narrow horizontal rectangular "Plastic" bar is embedded partway into the concrete and protrudes beyond the concrete right edge. A red arrow labelled "Force" pulls the exposed bar to the right. Four red-outlined circular position markers lie just below the embedded bar: from left to right D, C, B within the concrete, and A at the right-hand concrete boundary.