Four identical square plates of side a are arranged as shown. The equivalent capacity between points A and B is

• A

  $\frac{3{\epsilon }_0{a}^2}{2d}$

• B

  $\frac{3{\epsilon }_0{a}^2}{4d}$

• C

  $\frac{3{\epsilon }_0{a}^2}{5d}$

• D

  $\frac{{\epsilon }_0{a}^2}{2d}$