Charlotte completed an experiment in which she investigated and discovered that an electrically charged object can attract an uncharged object without any contact. She used a PVC pipe and small pieces of paper for her experiment. Each time, she rubbed the PVC pipe with a cloth to give it a charge and then held it over paper. What would be Charlotte's control group in this experiment?
1. Using the cloth and rubbing it against the PVC pipe
2. Taking the pieces of paper and rubbing it against the cloth
3. Not rubbing the cloth against the PVC pipe or the paper
4. Rubbing the cloth against both the paper and the PVC pipe
