The statement that is true about every public domain work is:
It is not protected by copyright or Creative Commons licenses.
Public domain works are no longer under copyright protection, which means they can be freely used by anyone without permission or the need for a license. The other statements may apply to many public domain works, but they are not universally true. For example, not all public domain works are 100 years old or considered to have great artistic or scientific merit, and public domain works can encompass a wide range of creative outputs beyond just art, literature, or music.