The correct answer is option 3, paramagnetic materials.

Option 1, magnetic materials, is incorrect because not all magnetic materials exhibit magnetic properties. Oxygen is not considered a magnetic material as it lacks a permanent magnetic field.

Option 2, ferromagnetic materials, is incorrect as well. Ferromagnetic materials have strong magnetic properties and can be permanently magnetized. Oxygen does not possess these characteristics.

Option 4, diamagnetic materials, is also incorrect. Diamagnetic materials are weakly repelled by a magnetic field. While oxygen does exhibit some weak diamagnetic properties, its overall magnetic behavior is better classified as paramagnetic.

Therefore, option 3, paramagnetic materials, is the best classification for oxygen`s magnetic properties. Paramagnetic materials are weakly attracted to a magnetic field and result in a temporary magnetization when exposed to a magnetic field.