What can be inferred from paragraphs 4 and 5 about soil conservation efforts in the United States A. Encouraging minimum tillage practices resulted in much more efficient soil conservation than converting erodible land into vegetative cover. B. Complete retirement of land combined with soil-conservation practices significantly reduced soil erosion. C. Measuring the success of government-supported conservation programs over extended periods of time was sometimes as difficult as getting the programs started. D. The reduction of energy use due to practices such as conservation tillage and land retirement was much larger in the United States than in any other country.