Sophisticated laser-guided land graders can now flatten uneven farmland almost perfectly so as not to waste rainwater in runoff down sloping fields.

(A) so as not to waste rainwater
(B) so that rainwater is not wasted
(C) so that there is no wasted rainwater
(D) and thereby not waste rainwater
(E) and there is no rainwater wasted



OA B

Source: Official Guide