The correct response is:
The process of dissolving frees the electrons in the solution to move.
When salt (sodium chloride, for example) is dissolved in water, it dissociates into its constituent ions (sodium ions and chloride ions). These ions are charged particles that are free to move within the solution, allowing it to conduct electricity. In contrast, pure water and solid salt do not have these mobile charged particles, which is why they do not conduct electricity well.