In which of the following pπ-dπ bonding is possible ?

The π bond in  PO4-3 is formed by the overlapping of d - orbitals of "p" & p-orbitals of oxygen, & the formed π-bond is said to be dπ-pπ bond.In CO3-2,NO3-,NO2-  the central atom donot have empty d-ortials in its valency shell therefore these central atoms donot form the dπ-pπ bond.