Students in the metropolitan school district lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming ever more dependent on information based industries.

A: lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming
B: lack math skills to a large enough degree that they will be difficult to absorb into a city's economy that becomes
C: lack of math skills is so large as to be difficult to absorb them into a city's economy that becomes
D: are lacking so much in math skills as to be difficult to absorb into a city's economy becoming
E: are so lacking in math skills that it will be difficult to absorb them into a city economy becoming.

Please explain the difference