Which of the following statement are correct?

i)   In octahedral complexes, $d_{z^2},d_{x^2-y^2}$  orbitals have higher energy than $d_{xy},d_{yz}and{d}_{zx}$ orbitals

ii)  In tetrahedral complexes, $d_{xy},d_{yz},d_{zx}$ orbitals have higher energy than $d_{z^2}and{d}_{x^2-y^2}$orbitals

iii) The colors of complexes are due to electronic transitions from one set of d-orbitals to another set of orbitals.

vi) ${\Delta }_{tetrahedral}=\frac{9}{4}{\Delta }_{octahedral}$