Physics · Electrostatic Potential

Four charges are arranged at the corners of a square ABCD of side \( d \), with \( +q \) at A and C, and \( -q \) at B and D. The total electrostatic potential energy of this configuration is:

1. A
   \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 4 - \frac{1}{\sqrt{2}} ) \) / \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 4 - \frac{1}{\sqrt{2}} ) \)
2. B
   \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 2 - \frac{1}{\sqrt{2}} ) \) / \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 2 - \frac{1}{\sqrt{2}} ) \)
3. C
   \( \frac{q^2}{4\pi\varepsilon_0 d} ( 4 + \frac{1}{\sqrt{2}} ) \) / \( \frac{q^2}{4\pi\varepsilon_0 d} ( 4 + \frac{1}{\sqrt{2}} ) \)
4. D
   \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 2 + \frac{1}{\sqrt{2}} ) \) / \( -\frac{q^2}{4\pi\varepsilon_0 d} ( 2 + \frac{1}{\sqrt{2}} ) \)