Th correct answer to this question would be, Insulator. Notice in the question it says "Material". The question is basically asking, What item resists the flow of and electric current. A resistor is a device that suppose to strain the electric current. And resistance is the measure of how well the material can conduct an electric charge. With all of that being stated, Insulator materials include paper, dry wood, rubber, glass, ect. Insulator products provides resistance.
Make sure you read the questions very carefully.