Identify the type of isomerism exhibited by the complex compounds: $[Cr(H_2O)_6]Cl_3$ and $[Cr(H_2O)_5Cl]Cl_2 \cdot H_2O$.

The increasing order of magnetic moments for the following complexes is:
$I$. $[Fe(CN)_6]^{4-}$
$II$. $[Fe(CN)_6]^{3-}$
$III$. $[Cr(NH_3)_6]^{3+}$
$IV$. $[Ni(H_2O)_4]^{2+}$

The ratio of spin-only magnetic moment values $\mu_{eff}[Cr(CN)_6]^{3-} / \mu_{eff}[Cr(H_2O)_6]^{3+}$ is $.........$.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The total number of geometrical isomers shown by $[Co(en)_2 Cl_2]^{+}$ complex ion is three.
Reason $R$: $[Co(en)_2 Cl_2]^{+}$ complex ion has an octahedral geometry.
In the light of the above statements,choose the most appropriate answer from the options given below:

The spin-only magnetic moments of $[Fe(NH_3)_6]^{3+}$ and $[FeF_6]^{3-}$ in $BM$ are,respectively

The total possible coordination isomers for the following compounds respectively are :
$[Co(en)_3] [Cr(C_2O_4)_3]$
$[Cu(NH_3)_4] [CuCl_4]$
$[Ni(en)_3] [Co(NO_2)_6]$