Which of the following complexes will exhibit optical isomerism?

Given below are two statements:
Statement-$I$: $[Fe(ox)_3]^{3-}$ is chiral.
Statement-$II$: $trans-[Cr(H_2O)_2(ox)_2]^-$ is chiral.
(Given: $oxH_2 = HOOC-COOH$)
In light of the above statements, choose the most appropriate answer from the options given below:

Which of the following polymerisation isomers of the compound having empirical formula $Cr(NH_3)_3(NO_2)_3$ has the lowest molecular mass?

The most paramagnetic complex is

In the coordination compound $[Co(en)_2Cl_2]Cl$,which of the following statements is false?

$CoSO_{4}Cl \cdot 5NH_{3}$ exists in two isomeric forms '$A$' and '$B$'. Isomer '$A$' reacts with $AgNO_{3}$ to give white precipitate,but does not react with $BaCl_{2}$. Isomer '$B$' gives white precipitate with $BaCl_{2}$ but does not react with $AgNO_{3}$. Answer the following questions.
$(i)$ Identify '$A$' and '$B$' and write their structural formulas.
$(ii)$ Name the type of isomerism involved.
$(iii)$ Give the $IUPAC$ name of '$A$' and '$B$.'