The Curie temperature is the temperature above which a ferromagnetic material becomes paramagnetic.

Ferromagnetic materials have a high degree of magnetization in the presence of a magnetic field. Above the Curie temperature, these materials lose their ferromagnetic behavior and become paramagnetic, meaning they are weakly attracted to a magnetic field and do not retain any magnetization in the absence of an external magnetic field.

So, the correct option is :

Option A : a ferromagnetic material becomes paramagnetic.