15. The North Pole of a bar magnet is slid across a nail from its tip end to its head end. The same process is repeated several times. How would you now describe the nail?

1. The nail is charged with its tip end a - and its head end a +.
2. The nail is charged with its tip end a + and its head end a -.
3. The nail is magnetized with its tip end a North Pole and its head end a South Pole.
4. The nail is not be magnetized.
5. The nail is magnetized with its tip end a South Pole and its head end a North Pole.