Answer:
A) surplus food
Explanation:
In order for a society to be able to develop, prosper, and start to specialize, the most crucial thing that the people have to have at disposal is a surplus of food. If there is a surplus of food, that means that the people will have secured their basic need and don't have to worry about it, and on top of that they have much more spare time. This security of food sources and spare time, results in a society where the jobs start to differentiate. Not all people are needed in the production of food, so some of them will use their skills and brains for other purposes, such as art, science, construction, metal-work etc. That will result in specialization of the people in numerous different professions, making up a vibrant society that prospers and develops in all directions.
