In a $d^4$ low spin complex,what will be the magnetic moment $(\mu)$ in $B.M.$ if the coordination number is $6$?

Which of the following is true for $[Fe(CN)_6]^{3-}$ and $[FeF_6]^{3-}$?

The $d-$electron configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour?
(At. nos. $Cr = 24, Mn = 25, Fe = 26, Co = 27$)

The complex showing a spin-only magnetic moment of $2.82 \ B.M.$ is

Which of the following complex species is not expected to exhibit optical isomerism? $(en = \text{ethylenediamine})$

Identify the diamagnetic complexes among the following complexes $K$ to $P$:
$(K)\ K_3[Fe(CN)_6]$
$(L)\ [Co(NH_3)_6]Cl_3$
$(M)\ Na_3[Co(ox)_3]$
$(N)\ [Ni(H_2O)_6]Cl_2$
$(O)\ K_2[Pt(CN)_4]$
$(P)\ [Zn(H_2O)_6](NO_3)_2$