Two uncharged metal balls, X and Y, stand on glass rods. A third ball Z, carrying a positive charge, is brought near the first two. A conducting wire is then run between X and Y. The wire is then removed, and ball Z is finally removed. When this is all done, it is found that:   1. Balls X and Y are still uncharged 2. Balls X and Y are both charged positively 3. Balls X and Y are both charged negatively 4. Ball X is positive and ball Y is negative 5. Ball X is negative and ball Y is positive