Which of the sentences below best expresses the essential information in the highlighted sentence in the passage. Incorrect answer choices change the meaning in important ways or leave out essential information. A. The innovation of this technique facilitated the utilized water from uncontrolled rivers. B. This allowed for the swampy marshlands near rivers to be uncontrolled by the rivers themselves. C. Fanners were now able to invest labor resources into the development of marshlands from rivers. D. Field leveling was a technique that allowed farmers to exploit the natural layout of their terrain.