Answer: D) All of the above
Step-by-step explanation:
Insulators have very tightly bound valence electrons which do not allow electricity to flow through them easily. This makes them poor conductors of electricity. Examples of insulators include ceramic, glass, rubber, and plastics. Since insulators do not allow the flow of electric charge, they are commonly used to prevent electric shock, to protect electrical equipment, and to maintain the electrical insulation between different parts of an electrical system.