Four statements are made about conductance. I. The molar conductivity of a weak electrolyte tends to its limiting value as the concentration goes to zero. II. The molar conductivity of a strong electrolyte does not change with the concentration. III. The conductivity of a strong electrolyte falls when its solution is diluted. IV. The limiting molar conductivity of a weak electrolyte is found by extending a straight line of $\Lambda_m$ against $\sqrt{c}$. Which statements are correct?