C) Uruk is considered the world's oldest known city in ancient Mesopotamia. Uruk was an ancient city located in present-day Iraq, situated on the Euphrates River. It was one of the major cities of Sumer, which was an ancient civilization that flourished in the Mesopotamian region.

I. Historical Background of Uruk:
Uruk was founded around 4500 BCE and its history spans over several centuries. It was a thriving city during the Uruk period (4100-2900 BCE), which is named after the city itself. The city expanded rapidly during this time, becoming the largest urban center of its time.

II. Urban Development:
1. Uruk was characterized by its impressive architecture, including monumental buildings and temples. The city had a complex layout with a network of streets and canals.
2. The city was surrounded by a massive defensive wall, which indicates the importance of defense and security in the ancient world.
3. Uruk was also an economic hub, with evidence of trade networks and a highly organized system of agriculture.

III. Cultural and Artistic Significance:
1. Uruk is known for its rich cultural and artistic heritage. The city was home to the famous Uruk Vase, a large ceremonial vessel decorated with intricate carvings depicting various scenes of ancient life.
2. The city was also associated with the development of writing. The earliest known form of writing, known as cuneiform, was developed in Uruk.

IV. Influence and Legacy:
1. Uruk had a significant influence on subsequent civilizations in the region. Its urban planning and architectural techniques were adopted by later Mesopotamian cities.
2. The Uruk period marked a turning point in human civilization, with the emergence of complex urban societies and the development of writing.

In conclusion, Uruk is considered the world's oldest known city in ancient Mesopotamia due to its early establishment, impressive urban development, cultural significance, and influence on subsequent civilizations. Its legacy as a center of innovation and urbanization makes it a crucial site for understanding the history of human civilization.