Concept:Conductivity (specific conductivity) of an electrolyte solution depends on the number of ions per unit volume. For a strong electrolyte, all solute molecules dissociate completely into ions.Explanation:On dilution, the total number of ions remains the same, but the volume of the solution increases. As a result, the concentration of ions per unit volume decreases. Since conductivity measures the ability of a given volume to conduct electricity, fewer ions in that volume lead to lower conductivity. Thus, the specific conductivity of a strong electrolyte decreases upon dilution. (Note: Molar conductivity increases with dilution, but the question asks about conductivity, which is specific conductivity.)Answer:A. Decreases on dilution