Which type of material always has two opposite poles that attract each other?

The correct answer is magnetic, as magnetic materials are characterized by the presence of two distinct poles: a north pole and a south pole. These poles exhibit attraction towards one another, with the north pole of one magnet attracting the south pole of another. This polarity is a fundamental property of magnets, allowing them to interact with each other and produce magnetic fields.

In contrast, conductive materials facilitate the flow of electricity but do not inherently possess poles like magnets. Insulating materials, on the other hand, resist the flow of electricity and also do not feature magnetic poles. Elastic materials are defined by their ability to return to their original shape after deformation, and they do not exhibit the magnetic characteristics of having opposite poles. Thus, the unique behavior of magnets in having two poles that attract one another is what makes the answer magnetic.