The true statement about every public domain work is:
It is not protected by copyright or Creative Commons licenses.
Public domain works do not have copyright protection, meaning they can be freely used by anyone without permission. The other statements are not universally true for all public domain works. For example, a work does not need to be 100 years old to be in the public domain, and not all public domain works are necessarily of great artistic or scientific merit or classified as art, literature, or music.