a positively-charged wool sock and a neutral plastic bag a neutral cotton sweater and a negatively-charged plastic pellet a negatively-charged balloon and a positively-charged piece of paper a negatively-charged plastic strip and a negatively-charged piece of cloth
Which pair of items will repel each other?

Options:
- a positively-charged wool sock and a neutral plastic bag
- a neutral cotton sweater and a negatively-charged plastic pellet
- a negatively-charged balloon and a positively-charged piece of paper
- a negatively-charged plastic strip and a negatively-charged piece of cloth

a negatively-charged plastic strip and a negatively-charged piece of cloth