Geometric isomerism is exhibited by which of the following coordination compounds?

An octahedral complex with molecular composition $M \cdot 5NH_3 \cdot Cl \cdot SO_4$ has two isomers,$A$ and $B$. The solution of $A$ gives a white precipitate with $AgNO_3$ solution and the solution of $B$ gives a white precipitate with $BaCl_2$ solution. The type of isomerism exhibited by the complex is

Which of the following compounds shows optical isomerism?

Which of the following complex ions is expected to absorb light in the visible region?

Identify the complex ion with spin only magnetic moment of $4.90 \ BM$.

Among the following complex ions,the one which shows geometrical isomerism will be