For (i) [Cr(C2O4)3]3-, this is a homoleptic complex where all three ligands are identical (oxalate is a bidentate ligand). Since geometrical isomerism arises in heteroleptic complexes due to different possible geometric arrangements of ligands, no geometrical isomers are possible when all ligands are the same. For (ii) [Co(NH3)3Cl3], this is a heteroleptic complex with three NH3 and three Cl ligands in an octahedral arrangement. Two geometrical isomers are possible: the facial (fac) isomer where three identical ligands occupy one face of the octahedron, and the meridional (mer) isomer where three identical ligands occupy positions around the meridian.