Question

Which one of the following substances has infinitely high electrical resistance?

• A. conductor
• B. insulator
• C. super conductor
• D. resistor

Answer 1

The correct option is B insulator

Answer is B.
An electrical insulator is a material whose internal electric charges do not flow freely, and therefore make it very hard to conduct an electric current under the influence of an electric field. And those substances have infinite high electrical resistance.
Ideally, the insulation resistance would be infinite, but as no insulators are perfect, leakage currents through the dielectric will ensure that a finite (though high) resistance value is measured.