Which of the following compounds exhibits linkage isomerism?

Consider the complex ions,$trans-[Co(en)_2Cl_2]^+$ $(A)$ and $cis-[Co(en)_2Cl_2]^+$ $(B)$. The correct statement regarding them is :

$[Ti(H_2O)_6]^{3+}$ is paramagnetic in nature due to

Which of the following complexes has the possibility to exist as a meridional isomer?

Identify the complex compound$(s)$ which is/are optically active and whose optical activity does not depend upon the orientation of the ligands around the metal cation:
$(i). [CoCl_3(NH_3)_3]$
$(ii). [Co(en)_3]Cl_3$
$(iii). [Co(C_2O_4)_2(NH_3)_2]^-$
$(iv). [CrCl_2(NH_3)_2(en)]^+$

Total number of isomers possible for the complex $[Co(en)_2Cl_2]$ is