Which theory discussed the relationship between ligand bonding and degradation of d orbitals in  metal complexes and the geometry of metal complexes and the splitting of d orbitals ?

Crystal field theory (CFT)

The correct answer is option 1. Crystal field theory (CFT).

The theory that discusses the relationship between ligand bonding, the degradation of d orbitals in metal complexes, the geometry of metal complexes, and the splitting of d orbitals is the Crystal Field Theory (CFT). Therefore, the correct option is: Crystal Field Theory (CFT).