帮忙看道语法题！

In the last ten years, the dropout rate among Black high school students fell substantially over the past decade, while the number of Blacks who attend college is more than twice what it was.

(A)  fell substantially over the past decade, while the number of Backs who attend college is more than twice what it was.

(B)   fell substantially, while the number of Blacks attending college is more than double what it was at that time

(C)   has fallen substantially, while the number of Blacks attending college has more than doubled

(D)  has fallen substantially over the past decade, while the number of Blacks attending college is more than twice what it was at that time

(E)   has fallen substantially over the past decade, while the number of Blacks who are attending college are more than double what they were

over the past decade和前面的In the last ten years不是语意重复吗？