Final answer:
The Neolithic Revolution, marked by a shift to systematic agriculture, was the pivotal change for Neolithic peoples, leading to settled communities and the onset of civilization.
Step-by-step explanation:
The change that marked a transition to the Neolithic people was C. a shift to systematic agriculture. This pivotal shift is known as the Neolithic Revolution, and it represents the time when human populations moved from a nomadic hunter-gatherer lifestyle to one characterized by permanent settlements, the domestication of plants and animals, and the beginnings of agricultural production. This transition enabled larger settled communities, the development of complex societies, and ultimately, the rise of civilization.