Early human civilizations often developed near rivers and fertile floodplains primarily because these areas provided:

The correct answer to the question "Early human civilizations often developed near rivers and fertile floodplains primarily because these areas provided:" is Option C: Reliable sources of water for agriculture and transportation..

The other options — A) Natural barriers against invading armies., B) Easy access to trade routes with distant empires., D) Abundant mineral resources for tool-making. — are incorrect for this GED Exam Prep question. As explained above: Rivers provided fresh water for drinking and irrigation, essential for agriculture, which allowed for stable food supplies and population growth, leading to the development of civilizations.