Final answer:
The development of agriculture led directly to the development of complex civilizations, as it supported population growth, social hierarchies, labor specialization, and resource accumulation.
Step-by-step explanation:
The development of agriculture in the regions shown on the chart had several direct effects. However, the most prominent one, represented by choice B, is the development of complex civilizations. Farming allowed human societies to transition from nomadic hunter-gatherer lifestyles to settled agricultural ones, which fostered population growth and the establishment of stable communities. This, in turn, led to the development of social hierarchies, specialization of labor, and an accumulation of resources that would be foundational for the establishment of complex civilizations. Over time, as agriculture became more efficient and capable of producing surpluses, societies began developing systems of writing, trade, governance, and culture that characterized complex civilizations.