The spin magnetic moment of cobalt in the compound $Hg[Co(SCN)_4]$ is (in $B.M.$)

The total number of possible isomers for the complex compound $[Cu^{II}(NH_3)_4][Pt^{II}Cl_4]$ are

Among $(i)$ $[Cr(en)_{3}]^{3+}$,$(ii)$ $trans-[Cr(en)_{2}Cl_{2}]^{+}$,$(iii)$ $cis-[Cr(en)_{2}Cl_{2}]^{+}$,$(iv)$ $[Co(NH_{3})_{4}Cl_{2}]^{+}$,the optically active complexes are:

$Fac$ and $Mer$ isomerism is associated with which of the following general formula?

Which of the following will show optical isomers?
$I$. $\text{cis}-[Co(NH_3)_2(en)_2]^{3+}$
$II$. $\text{trans}-[IrCl_2(C_2O_4)_2]^{3-}$
$III$. $[Rh(en)_3]^{3+}$
$IV$. $\text{cis}-[Ir(H_2O)_3Cl_3]$

Consider the following isomerism:
$i$. Ionization
$ii$. Hydrate
$iii$. Coordination
$iv$. Geometrical
$v$. Optical
Which of the above isomerisms are exhibited by $[Cr(NH_3)_2(OH)_2Cl_2]^-$?