Which of the following complexes does not exhibit optical isomerism?

Which of the following complexes shows ionization isomerism?

Which one of the following coordination complexes exhibits the lowest value of magnetic moment (in $BM$)?

The type of isomerism between $[Co(en)_2(NCS)_2]Cl$ and $[Co(en)_2(NCS)Cl]NCS$ is ............ .

Which of the following pairs of isomers and their types of isomerism are correct? Select the correct option.
$(1)\ [Co(NH_3)_5(NO_2)]Cl_2$ and $[Co(NH_3)_5(ONO)]Cl_2$: Linkage isomerism
$(2)\ [Cu(NH_3)_4][PtCl_4]$ and $[Pt(NH_3)_4][CuCl_4]$: Coordination isomerism
$(3)\ [Pt(NH_3)_4Cl_2]Br_2$ and $[Pt(NH_3)_4Br_2]Cl_2$: Ionization isomerism

The complex having the highest spin-only magnetic moment is