Number of Complexes with even number of electrons in t_ 2 g...

Number of Complexes with even number of electrons in $t_{2 g}$ orbitals is - (\left[\mathrm{Fe}\left(\mathrm{H}}_{2} \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Co}\left(\mathrm{H}}_{2} \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Co}\left(\mathrm{H}}_{2} \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{Cu}\left(\mathrm{H}}_{2} \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Cr}\left(\mathrm{H}}_{2} \mathrm{O}\right)_6\right]^{2+})