In which of the following complexes will the $CFSE$ (Crystal Field Stabilization Energy),$\Delta_0$ be equal to zero?

Homoleptic octahedral complexes of a metal ion $M^{3+}$ with three monodentate ligands $L_1, L_2$ and $L_3$ absorb wavelengths in the region of green,blue and red respectively. The increasing order of the ligand strength is:

What is the electronic arrangement of a metal atom/ion in an octahedral complex with $d^4$ configuration,if $\Delta_0 < P$ (pairing energy)?

The electronic configuration of $Cr$ in $Cr(CO)_6$ as calculated using crystal field theory is

For which of the following complexes will the value of $\Delta_0$ be the lowest?

Which sets of the $d$-orbitals are directly oriented towards the ligands in octahedral coordination compounds?