A charge $+q$ is fixed at each of the points $x = x_0, x = 3x_0, x = 5x_0, \dots, \infty$ on the $x$-axis, and a charge $-q$ is fixed at each of the points $x = 2x_0, x = 4x_0, x = 6x_0, \dots, \infty$. Here $x_0$ is a positive constant. Take the electric potential at a point due to a charge $Q$ at a distance $r$ from it to be $Q/(4\pi\varepsilon_0 r)$. Then, the potential at the origin due to the above system of charges is:

• A
  $0$
• B
  $\frac{q}{8\pi\varepsilon_0 x_0 \ln 2}$
• C
  $\infty$
• D
  $\frac{q \ln 2}{4\pi\varepsilon_0 x_0}$