Answer:
Isoelectric focusing Ion-exchange chromatography.
Step-by-step explanation:
Proteins are the polymers made of the monomers of the alpha amino acids linked through the peptide bond. The proteins may be neutral as well some contains the charge over them.
The proteins on the basis of the charge can be separated by ion exchange chromatography and isoelectric focusing. These techniques have different solutes and solvents that separate proteins on charge basis. SDS-PAGE separates the protein on their weight and Affinity chromatography separates protein on their binding with ligand.
Thus, the answer is only II and III .