Electrostatics: JEE Main 2025 Physics question

In the first configuration (1) as shown in the figure, four identical charges ($q_0$) are kept at the corners A, B, C and D of square of side length 'a'. In the second configuration (2), the same charges are shifted to mid points G, E, H and F, of the square. If $K = \frac{1}{4\pi\epsilon_0}$, the difference between the potential energies of configuration (2) and (1) is given by: