Just did a google on this one and found out that Manhattan will "edit" this question from their books.
I wouldn't put to much effort into this question since there's only a slight difference between D) and E).
If you compare 'high enough' and 'so x as to y' there's a difference in what they say. Looking at A we find that 'so x as to y' is correct here (if we want to keep the meaning) and consequently E is correct.
12/2010 GMATPrep 1 620 (Q34/V41)
01/2011 GMATPrep 2 640 (Q42/V36)
01/2011 GMATPrep 3 700 (Q47/V39)
02/2011 GMATPrep 4 710 (Q48/V39)
02/2011 MGMAT CAT 1 650 (Q46/V32)
02/2011 MGMAT CAT 2 680 (Q46/V36)
02/2011 MGMAT CAT 3 710 (Q45/V41)