c
\((I)\) Under weak field ligand, octahedral \(Mn(II)\) and tetrahedral \(Ni(II)\) both the complexes are high spin complex.

\((II)\) Tetrahedral \(Ni(II)\) complex can very rarely be low spin because square planar (under strong ligand) complexes of \(Ni ( II )\) are low spin complexes.

\((III)\) With strong field ligands \(Mn (II)\) complexes can be low spin because they have less number of unpaired electron (unpaired electron \(=1\) )

While with weak field ligands \(Mn(II)\) complexes can be high spin because they have more number of unpaired electron (unpaired electron \(=5)\)

\((IV)\) Aqueous solution of \(Mn(II)\) ions is pink in colour.