How many statements is/are correct for given complex $\left[\mathrm{C}\mathrm{o}\right({\mathrm{C}}_2{\mathrm{O}}_4{)}_3{]}^{3-}$
$\mathrm{i})\mathrm{}$ It contain negative ligands only
$\mathrm{i}\mathrm{i})\mathrm{}$ The oxidation state of central metal atom is $+3$
$\mathrm{i}\mathrm{i}\mathrm{i})\mathrm{}$ It is optically active
$\mathrm{i}\mathrm{v})\mathrm{}$ Due to chelation the stability of the complex increases
$\mathrm{v})\mathrm{}$ It exhibit geometrical isomerism
$\mathrm{v}\mathrm{i})\mathrm{}$ It is octahedral with ${\mathrm{d}}^2\mathrm{s}{\mathrm{p}}^3$ hybridization.
$\mathrm{v}\mathrm{i}\mathrm{i})\mathrm{}$ All oxalate ligands are replaced by ethylenediamine, then complex do not show optical activity.