A permanent magnet would most likely be made from:

Permanent magnets require materials that are ferromagnetic, meaning their atomic magnetic domains can be aligned and will retain that magnetic state over time. Steel, which is an alloy composed primarily of iron, possesses high magnetic retentivity, making it an excellent and common choice for permanent magnets. The other materials listed—aluminum, brass, and copper—are non-ferromagnetic. They cannot hold a magnetic field and are practically unaffected by magnets, making them entirely useless for creating a permanent magnet.