Ligand which has two different donor atoms and either of the two donor atom is attached to the metal during complex formation is called ambidentate ligand. Among the given ligands NCS−(SCN−)andNO2−(ONO−) are ambidentate ligands
C2O42−(bidentate),ethylenediamine(bidentate) and H2O(monodentate) ligands are not ambidentate.