Final answer:
Option (D), Mesopotamia's economic success was a result of its sophisticated irrigation systems, control over water, robust trade networks including travel by water, and strategic location for long-distance trade routes like the Silk Roads.
Step-by-step explanation:
The economic success of Mesopotamia can be attributed to a variety of factors including the control of water through extensive irrigation, which led to abundant agricultural production, long-distance trade, and the acquisition of vital resources like stone, timber, and metal ores through tribute or trade. Travel by water facilitated commerce, allowing traders to reach distant regions and exchange goods. Significant urban centers such as Ur, Babylon, and Nineveh succeeded due in part to surplus food enabling a strong administrative class, craft specialization, and the development of a military to protect and expand their interests.
Another key contributor to Mesopotamia's wealth was the strategic control over trade routes. Old Assyrian period records indicate active trade with distant areas like Anatolia and Afghanistan for copper and tin to make bronze. This trade network continued throughout various empires, with routes like the Silk Roads later becoming important for international commerce.