Which of the following compounds does not exhibit optical isomerism? $(en = \text{ethylenediamine})$

Three complex compounds $I$,$II$ and $III$ have Blue,Red and Green colour respectively. Which of the following orders of $\lambda_{abs}$ (absorbed wavelength) is $CORRECT$?

Out of the following two coordination entities,which is chiral (optically active)?
$(a)$ $cis-[CrCl_{2}(ox)_{2}]^{3-}$
$(b)$ $trans-[CrCl_{2}(ox)_{2}]^{3-}$

Coordination isomerism is caused by the interchange of ligands between the

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.

How many geometrical isomers does $[Pt(NH_3)(Br)(Cl)(Py)]$ have?