Out of the following which is an insulating material?

The correct answer is D. Paper.

Paper is an insulating material because it is made up of cellulose fibers that are bonded together with a weak adhesive. This makes it difficult for electricity to flow through paper, which is why it is often used to insulate electrical wires and cables.

Copper, gold, and silver are all metals that are good conductors of electricity. This means that electricity can flow easily through them. Therefore, they are not insulating materials.

In addition to paper, there are many other insulating materials, such as rubber, plastic, and glass. These materials are all used to prevent the flow of electricity in a variety of applications.