How many geometrical isomers are possible for the square planar complex $[Pt(NO_2)(Py)(NH_3)(NO_2)]$?

Which of the following is incorrectly matched?
Complex $-$ Number of unpaired electrons

Which of the following is diamagnetic?

Which of the following complexes will show coordination isomerism?
$A. [Ag(NH_3)_2][Ag(CN)_2]$
$B. [Co(NH_3)_6][Cr(CN)_6]$
$C. [Co(NH_3)_6][Co(CN)_6]$
$D. [Fe(NH_3)_6][Co(CN)_6]$
$E. [Co(NH_3)_6][Fe(CN)_6]$
Choose the correct answer from the options given below:

Which kind of isomerism is exhibited by the octahedral complex $Co(NH_3)_4Br_2Cl$?

Identify the diamagnetic complexes among the following complexes $K$ to $P$:
$(K)\ K_3[Fe(CN)_6]$
$(L)\ [Co(NH_3)_6]Cl_3$
$(M)\ Na_3[Co(ox)_3]$
$(N)\ [Ni(H_2O)_6]Cl_2$
$(O)\ K_2[Pt(CN)_4]$
$(P)\ [Zn(H_2O)_6](NO_3)_2$