The complex that can show $fac-$ and $mer-$isomers is

The spin-only magnetic moment value of the square planar complex $[Pt(NH_3)_2 Cl(NH_2 CH_3)] Cl$ is $B.M.$ (Nearest integer). (Given atomic number for $Pt = 78$)

Which of the following complexes will exhibit the highest number of isomers?

The correct statement on the isomerism associated with the following complex ions,
$A$. $[Ni(H_2O)_5NH_3]^{2+}$
$B$. $[Ni(H_2O)_4(NH_3)_2]^{2+}$ and
$C$. $[Ni(H_2O)_3(NH_3)_3]^{2+}$ 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:

Calculate the total number of stereoisomers for the octahedral complex $[Fe(F)(Cl)(Br)(I)(NH_3)(H_2O)]^-$.