The correct statement that explains why the solution conducts electricity well when salt is dissolved in water is:
The process of dissolving frees the atoms in the solution to move.
When salt (sodium chloride) is dissolved in water, it separates into its constituent ions (sodium ions and chloride ions). These free ions can move throughout the solution, allowing the solution to conduct electricity effectively. Pure water and solid salt do not have these free-moving charged particles, which is why they are poor conductors of electricity.