Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. The transgenic crop plants currently in use are probably far behind the transgenic plants of the future in terms of their sustainability. B. Farmers who use transgenic crop plants are heading toward practices that allow natural resources to continually regenerate over the long run. C. Transgenic crop plants may be used in place of other, more sustainable agricultural practices, and this is perhaps their biggest disadvantage. D. Perhaps the most serious concern about the transgenic crop plants currently in use is the possibility that they may not be sustainable over the long run.