The following evidence was gathered to support the idea that education and outreach programs in the past neglected the African people's existing knowledge regarding farming methods. During the colonial era, state governments tried to force peasants and farmers to adopt scientifically approved farming techniques.
Many of these efforts were aimed at controlling African populations and did not take into account significant cultural norms.
Not surprisingly, most nationalist governments in the post-independence era tried to work with rural populations rather than force change.
What additional piece of evidence helps to create the MOST COMPLETE argument that education and outreach programs in the past neglected the African people's existing knowledge regarding farming methods?

A
Overgrazing and poor farming techniques can also lead to soil erosion, but it is important to remember that not all causes are human; climate and natural soil quality are also important factors to consider in tropical and mountainous regions.
B
They favored education and outreach programs, but soil erosion and poor output continued, in part because no one looked carefully at what farmers and herders were actually doing.
C
Recently, more research has gone into both the causes of soil erosion and into what are termed indigenous farming methods and knowledge about sustainable use.
D
Some farming patterns are destructive, and research can identify better ways, but increasingly scholars and policymakers are emphasizing the need to draw the best from scientific research and peasant knowledge of the land.