The species that can have a trans-isomer is :

$\left[\mathrm{Pt}(\mathrm{en}) \mathrm{Cl}_{2}\right]$

$\left[\mathrm{Cr}(\mathrm{en})_{2}(\mathrm{ox})\right]^{+}$

$\left[\mathrm{Zn}(\mathrm{en}) \mathrm{Cl}_{2}\right]$

$\left[\mathrm{Pt}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]^{2+}$