The true statement about every public domain work is:
It is not protected by copyright or Creative Commons licenses.
Public domain works are those that are free from copyright restrictions, meaning they can be freely accessed, used, and distributed by anyone. While many public domain works may be art, literature, or music, not all of them are necessarily recognized for exceptional artistic or scientific merit, and being 100 years old is not a strict requirement for all public domain works, as laws regarding copyright can vary.