The highest value of the calculated spin-only magnetic moment (in $BM$) among all the transition metal complexes is

In an octahedral complex of the type $Ma_3b_3$,where $M$ is a metal ion and $a$ and $b$ are two different types of ligands,what are the two possible geometric isomers?

Among the following options,select the option in which each complex in Set-$I$ shows geometrical isomerism and the two complexes in Set-$II$ are ionization isomers of each other.
$[en = H_2N-CH_2-CH_2-NH_2]$

Among the species given below,the total number of diamagnetic species is. . . . . $H$ atom,$NO_2$ monomer,$O_2^{-}$ (superoxide),dimeric sulphur in vapour phase,$Mn_3O_4$,$(NH_4)_2[FeCl_4]$,$(NH_4)_2[NiCl_4]$,$K_2MnO_4$,$K_2CrO_4$

What is the value of spin-only magnetic moment for $Cu^{2+}$ in $BM$?

Among $(a) - (d)$,the complexes that can display geometrical isomerism are:
$(a) [Pt(NH_3)_3 Cl]^+$
$(b) [Pt(NH_3) Cl_5]^-$
$(c) [Pt(NH_3)_2 Cl(NO_2)]$
$(d) [Pt(NH_3)_4 ClBr]^{2+}$