Where among the following metal complexes the one which exhiibits optical activity is: (AA=bidentate ligand, A, X=monodentate ligand)

Which one is bidentate ligand?

Which one is bidentate ligand:

Which one is monodentate ligand:

Which is not a bidentate ligand?

Which is not a bidentate ligand?

Fac-Mer isomerism is associated with which of the following types of complexes ? (M is the central metal. A-A is a symmetrical bidentate ligand. A,B,C & D are monodentate ligands)