Which of the following is a characteristic of insulators?

Insulators are materials that impede the flow of electric current. A key characteristic of insulators is their ability to restrict current flow, which is why they are commonly used to prevent unwanted passage of electricity. This restriction occurs due to the atomic structure of insulators; their electrons are tightly bound to their atoms and do not move freely. As a result, insulators exhibit high resistance to electrical current, making them effective in preventing electrical conduction.

The other options pertain to conductors or materials that facilitate electricity flow rather than insulating materials. High conductivity and low resistance describe materials that allow for easy electron movement, which is opposite the behavior seen in insulators. Enhanced electron movement is also indicative of conductive materials where free electrons are available to carry current, further contrasting the properties of insulators.