Which of the following best describes magnetic fields

Magnetic fields have north and south magnetic poles.

Explanation:

Magnetic fields are generated whenever charge is in motion. Magnets are those materials that have the capability to generate magnetic fields.

Magnetic fields have various characteristics which includes; they originate from the north poles and flow towards the south poles, they are exhibited in the form of magnetic field lines. Magnetic fields lines never cross one another, they all have the same strength and seek the path of least resistance between opposite magnetic poles etc.