In an octahedral complex $[Mabcdef]$,the total number of theoretical isomers is:

The number of possible stereoisomers for the complex $[Co(en)_2Cl_2]Cl$ is $(en = \text{ethylenediamine})$.

Which of the following complexes exhibit geometrical isomerism?
$I$) $[Co(en)(NH_3)_2 Cl_2] Cl$
$II$) $[Co(NH_3)_4 Cl_2] Cl$
$III$) $[Co(en)_3] Cl_3$
$IV$) $[Co(en)_2 Cl_2] Br$

Given below are two statements:
Statement-$I$ : The number of paramagnetic species among $[CoF_6]^{3-}$, $[TiF_6]^{3-}$, $V_2O_5$ and $[Fe(CN)_6]^{3-}$ is $3$.
Statement-$II$ : $K_4[Fe(CN)_6] < K_3[Fe(CN)_6] < [Fe(H_2O)_6]SO_4 \cdot H_2O < [Fe(H_2O)_6]Cl_3$ is the correct order in terms of number of unpaired electron$(s)$ in the complexes.
In the light of the above statements, choose the correct answer from the options given below.

Which type of isomerism is exhibited by the isomers $[Co(NH_3)_5(SO_4)]Br$ and $[Co(NH_3)_5Br]SO_4$?

The two complexes given below are $............$.