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

According to crystal field theory, for which of the following coordination entities is $\Delta_o$ maximum?

Which relationship is correct for the crystal field splitting energy between octahedral $(\Delta_0)$ and tetrahedral $(\Delta_t)$ complexes?

Given below are two statements:
Statement $I$: Among $Zn$, $Mn$, $Sc$ and $Cu$, the energy required to remove the third valence electron is highest for $Zn$ and lowest for $Sc$.
Statement $II$: The correct order of the following complexes in terms of $CFSE$ is $[Co(H_2O)_6]^{2+} < [Co(H_2O)_6]^{3+} < [Co(en)_3]^{3+}$.

The complex ion having minimum magnitude of $\Delta_{0}$ $(CFSE)$ is

Complexes with $CN^-$ ligands are generally...