Total number of relatively more stable isomer(s) possible for octahedral complex Cu en 2 SCN 2 will be____

This octahedral complex is of $\left[\mathrm{M}(\mathrm{AA}{)}_2{\mathrm{b}}_2\right]$ type structure in which AA is bidentate ligand and b is monodentate ligand. This can exist in two geometrical isomeric form cis and trans. Out of which trans form is relatively more stable isomer. Now due to ambidentate ligand ${\mathrm{SCN}}^{-}$ it can also shows linkage isomersim.

$\left[\mathrm{Cu}{\left(\mathrm{en}\right)}_2{\left(\mathrm{SCN}\right)}_2\right]$

So, relatively more stable trans isomers will have three possible isomers.