Answer:
D. The electrons are trapped in the crystal lattice structure and cannot move.
Step-by-step explanation:
Ionic compounds are compounds that consist of positive and negative ions that are held together by the electrostatic forces of attraction. In the solid phase, these ions are arranged in a regular, repeating pattern known as a crystal lattice. The ions are held in place by the electrostatic forces of attraction, and the electrons are trapped within the crystal lattice structure. Because the ions and electrons are unable to move freely, ionic compounds do not conduct electricity in the solid phase.