Agriculture turned humans from hunter gatherers into a more organized and civilized species. Because of people settling down to farm, citites were born because more people collected themselves around their main source of food. This also introduced the "division of labor" aspect of human evolution. Different families, now living in communites, could each be in charge of a specific task to help further their survival. Instead of each family having to do everything for themselves (churning butter, making clothes, building houses, etc.) one family would take on one of these tasks and produce their trade for the whole community and barter with the rest of the community for what they still needed. This led to the creation of jobs, money, and basically all of the social and economical commerce we know today.
I think it might be D. Although I am not a genius there were a few Greek uprisings and the Persians had one simple rule that you had to follow, don't ever, EVER betray them.
