The body will topple when the normal force passes through the edge. The force diagram at this stage is shown in figure.
taking torque about point A we have
mg (1/2)= 4F
F = (1/8)Mg = 0.125 mg
The force required for the body to move by translation is 0.2 mg, but the body topples when the force is 0.125 mg. Therefore, it is obvious that the body will topple before it translates.
