Spin only magnetic moment of $[MnBr_{6}]^{4-}$ is $..... \ B.M.$ (round off to the closest integer)

Consider the following low-spin complexes: $K_3[Co(NO_2)_6]$,$K_4[Fe(CN)_6]$,$K_3[Fe(CN)_6]$,$Cu_2[Fe(CN)_6]$,and $Zn_2[Fe(CN)_6]$. The sum of the spin-only magnetic moment values of complexes having yellow colour is $.......... B.M.$ (answer is nearest integer).

The calculated magnetic moments (spin only value) for species $[FeCl_{4}]^{2-}$,$[Co(C_{2}O_{4})_{3}]^{3-}$ and $MnO_{4}^{2-}$ respectively are ..... .

Which of the following complex ions is expected to absorb visible light?
[At. nos. $Zn = 30$,$Sc = 21$,$Ti = 22$,$Cr = 24$]

The number of isomers possible for the complex $K_2[PtClBr_2(SCN)]$ is:

Which of the following exhibits optical isomerism?