B.
For those that could not write (So most), they carried a seal around either on a necklace or otherwise that they could use to stamp with ink to signify 'signing' something.
They actually played a pretty important role in early civilizations. For one, building a major urban civilization takes a lot of work. Slaves could be used for building projects to enlarge the city and its defenses, for agricultural labor to ensure that the people of the city could eat, or as domestic assistants to kings, lords, and shop-owners.
<span>It helped establish transatlantic trade routes to the Americas.</span>
Menes united Upper and Lower Egypt. He was also known as Narmer.