Final answer:
The invalid reason for the development of urbanization in Mesopotamia is surplus availability of minerals, as the region lacked natural resources and had to trade its agricultural surplus to obtain them.
Step-by-step explanation:
The development of urbanization in Mesopotamia cannot be attributed to the surplus availability of minerals as one of its foundational factors. Considering the historical context of Mesopotamia, it is known that the region lacked stone, precious metals, and timber, and thus it had to rely on the long-distance trade of its agricultural production to secure these materials. The true drivers behind urbanization in the area were surplus agricultural production, efficient transportation, and the establishment of strong social and government structures that managed resources and supported urban growth.
Hence, the correct answer to the question 'Which of these is not a valid reason for development of urbanization in Mesopotamia?' is b) Surplus availability of minerals.