$[Co(NH_3)Cl(en)_2]^{2+}$ shows two geometrical isomers,$cis$ and $trans$. Which of the following statements is correct?

Among the following,the compound that is both diamagnetic and coloured is

$[Cr(NH_3)_6]^{3+}$ is paramagnetic while $[Ni(CN)_4]^{2-}$ is diamagnetic. Explain why?

The correct order of the calculated spin-only magnetic moments of complexes $A$ to $D$ is:
$A$. $Ni(CO)_{4}$
$B$. $[Ni(H_{2}O)_{6}]Cl_{2}$
$C$. $Na_{2}[Ni(CN)_{4}]$
$D$. $PdCl_{2}(PPh_{3})_{2}$

The complexes $[Co(NH_3)_6][Cr(CN)_6]$ and $[Cr(NH_3)_6][Co(CN)_6]$ are the examples of which type of isomerism?

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.