Final answer:
The form embodied by Sumerian ziggurats is a Pyramid, characterized by their stepped, terraced pyramid shape with a flat top.
Step-by-step explanation:
The symbolic form embodied by the Sumerian ziggurats is C. Pyramid. A ziggurat is an immense stepped tower with a flat top built of mud-brick that served as a temple in Sumerian cities. They had the form of a terraced pyramid with successively receding stories, constructed primarily for religious purposes while also serving significant administrative roles within the city-states of ancient Mesopotamia.
Ziggurats, standing as the centerpieces of these cities, symbolized not only a connection to the divine but also represented the political authority of the theocracy within these early civilizations. Their stepped, pyramid-like design with a flat summit and a temple at the top, typically located at the center of town, was part of the wider temple complex and distinguished from other forms like the circle, square, or cylinder.