Which one of the following complexes is violet in colour?
\( [\mathrm{Fe}(\mathrm{CN})_5\,\mathrm{NOS}]^{4-} \)
\( \mathrm{Fe_4[Fe(CN)_6]_3 \cdot H_2O} \)
\( [\mathrm{Fe}(\mathrm{CN})_6]^{4-} \)
\( [\mathrm{Fe}(\mathrm{SCN})_6]^{4-} \)