Which of the following pairs represents linkage isomers ?

$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{NO}_{3}\right] \mathrm{SO}_{4}$ and $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{SO}_{4}\right] \mathrm{NO}_{3}$

$\left[\mathrm{PtCl}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Br}_{2}$ and $\left[\mathrm{PtBr}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$

$\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{PtCl}_{4}\right]$ and $\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left[\mathrm{CuCl}_{4}\right]$

$\left[\mathrm{Pd}\left(\mathrm{PPh}_{3}\right)_{2}(\mathrm{NCS})_{2}\right]$ and $\left[\mathrm{Pd}\left(\mathrm{PPh}_{3}\right)_{2}(\mathrm{SCN})_{2}\right]$