A solution of known normality is diluted to two times. Which of the following changes during dilution?

On dilution since, volume of solution changes and thus, normality, molarity and $\text{ molality changes. The equivalent }\left(\frac{\text{ mass }}{\text{ eq. mass }}\right),\text{ mole }\left(\frac{\text{ mass }}{\text{ molar mass }}\right)\text{ do not change. }$