In general, substances with strong attractive forces between their particles tend to have high melting and boiling points and are solids at room temperature.
Salt (sodium chloride) is a solid at room temperature and has a relatively high melting point of 801°C. This is due to the strong attractive forces between its ions (positively charged sodium ions and negatively charged chloride ions).
Sugar (sucrose) is also a solid at room temperature but has a much lower melting point of 186°C. This is because the attractive forces between the sugar molecules are not as strong as the forces between the ions in salt.
Wax is a soft solid at room temperature and has a relatively low melting point. The attractive forces between wax molecules are weaker than those in salt or sugar.
So, in terms of the strength of attractive forces between its particles, salt would be the strongest, followed by sugar and then wax.