The metal ion whose electronic configuration is not affected by the nature of the ligand and which gives a violet colour in non-luminous flame under hot condition in borax bead test is

Given below are two statements:
Statement $I$: $A$ solution of $[Ni(H_2O)_6]^{2+}$ is green in colour.
Statement $II$: $A$ solution of $[Ni(CN)_4]^{2-}$ is colourless.
In the light of the above statements,choose the most appropriate answer from the options given below:

How many pairs of enantiomers are possible for the following complex compound,$[M(AB)(CD)ef]^{n \pm}$ (where $AB, CD$ are unsymmetrical bidentate ligands,and $e, f$ are monodentate ligands)?

Which of the following complex compounds has the highest number of geometrical isomers?

Among $Ni(CO)_4$,$[Ni(CN)_4]^{2-}$,and $[NiCl_4]^{2-}$,which of the following statements is correct regarding their magnetic properties?

Which of the following is true about the complex $[PtCl_2(H_2O)(NH_3)]$?