Answer: does not exist.
- A does not exist
- B exists freely
- C is very common
- D is a north pole only
Correct answer: A. does not exist
Explanation: Magnetic poles always occur in north–south pairs; isolated monopoles have never been observed.
Magnetic field of a bar magnet: field lines emerge from the north pole and re-enter at the south pole outside the magnet, forming continuous closed loops. Image: Geek3, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Bar magnets, Earth's magnetism, and how different materials respond to an external magnetic field - diamagnetic, paramagnetic, and ferromagnetic behaviour.