Step 1: Interactions that stabilize molecular structures are of two broad kinds: covalent bonds, which share electron pairs, and non-covalent bonds (hydrogen bonds, electrostatic or ionic interactions and van der Waals forces).
Step 2: Covalent bonds, such as peptide bonds and disulphide bonds in proteins, involve actual sharing of electrons and have far higher bond energies than any non-covalent interaction. Hence covalent is the strongest interaction.
Step 3: The order of strength runs covalent then electrostatic (ionic) then hydrogen then van der Waals. Van der Waals forces are the weakest of all, so the remaining options are all weaker than covalent.