15. Which of the procedures below will produce a magnetized nail with its head end a South Pole?

I. Rub the S-pole of the magnet from the head (H) to the point (P) end of the nail and then P-to-H.

II. Rub the N-pole of the magnet from the head (H) to the point (P) end of the nail and then P-to-H.

III. Rub the N-pole of the magnet twice from the head to the point end of the nail.

IV. Rub the S-pole of the magnet twice from the head to the point end of the nail.

II and III

II and IV

I and III

I and II

I and IV