The set which does not have ambidentate ligand(s) is:
\( \mathrm{EDTA}^{4-} \), \( \mathrm{NCS}^{-} \), \( \mathrm{C_2O_4}^{2-} \)
\( \mathrm{NO_2}^{-} \), \( \mathrm{C_2O_4}^{2-} \), \( \mathrm{EDTA}^{4-} \)
\( \mathrm{C_2O_4}^{2-} \), \( \mathrm{NO_2}^{-} \), \( \mathrm{NCS}^{-} \)
\( \mathrm{C_2O_4}^{2-} \), ethylene diamine, \( \mathrm{H_2O} \)