3 things that make art beautiful are:
- Creativity
- The option to do whatever you like
- How art can change the lives of many people
The answer is "3). It appears to have been created to mark the unification of Egypt."
It isn't 1, as the Palette of Narmer is an Egyptian artwork, not Sumerian.
It isn't 2, as it doesn't feature cuneiform, but hieroglyphs.
It isn't 4, as the art isn't Mesopotamian, but Egyptian.