In which of the following ions is the spin-only magnetic moment the lowest?

Which of the following spin paramagnetic complexes shows both geometrical and optical isomerism?

Match List-$I$ with List-$II$.

List-$I$ (Complex)	List-$II$ (Spin only magnetic moment in $B$.$M$.)
$A$. $[Cr(NH_3)_6]^{3+}$	$I$. $4.90$
$B$. $[NiCl_4]^{2-}$	$II$. $3.87$
$C$. $[CoF_6]^{3-}$	$III$. $0.0$
$D$. $[Ni(CN)_4]^{2-}$	$IV$. $2.83$

Choose the correct answer from the options given below:

The total number of isomers for a square planar complex $[M(F)(Cl)(SCN)(NO_2)]$ is

The spin-only magnetic moment value of an octahedral complex among $CoCl_{3} \cdot 4NH_{3}$,$NiCl_{2} \cdot 6H_{2}O$ and $PtCl_{4} \cdot 2HCl$,which upon reaction with excess of $AgNO_{3}$ gives $2$ moles of $AgCl$ is $....$ $B.M.$ (Nearest Integer)

$A$ compound of a metal ion $M^{x+}$ $(Z = 24)$ has a spin-only magnetic moment of $\sqrt{15} \ BM$. The number of unpaired electrons in the compound is: