Final answer:
The surplus availability of minerals is not a valid reason for the development of urbanization in Mesopotamia as they lacked natural resources and had to trade for them using agricultural surpluses.
Step-by-step explanation:
Which of the following is not a valid reason for the development of urbanization in Mesopotamia? The answer is B) Surplus availability of minerals. Mesopotamia lacked many natural resources such as precious minerals, which they had to trade for using their surplus agricultural products. The main factors contributing to urbanization included an agricultural surplus, which supported a growing population and the development of non-agricultural jobs, efficient transportation to facilitate trade, and an administrative class which could coordinate complex societal functions. The abundance of fishing resources was not a significant factor in Mesopotamia's urban development, although it may have supported the general food supply.