请教一道语法题

most of Portugal's 250000 university students boycotted classes in a one-day strike to protest a law that requires them to contribute $330 a year toward the cost of higher education,previously paying $7 per year.
A、a year toward the cost of higher education,previously paying $7 per year

B、a year toward the cost of higher education,for which was previously paid $7 per year.                                  

 C、a year,compared to the previously $7 per year,toward the cost of higher education                                     

 D、a year toward the cost of higher education,instead of the $7 per year required previously                              

E、a year as opposed to the $7 per year required previously for the cost of higher education

此题选D

还有一个就是

13．For all his professed disdain of such activities, Auden was an inveterate literary gossip.
（A）For all his professed disdain of such activities
（B）Having always professed disdain for such activities
（C）All such activities were，he professed disdained and
（D）Professing that all such activities were disdained
（E）In spite of professions of disdaining all such activities

为什么选A呢？

还有一道题：

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 Blacks 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

答案是選E的，可我怎麼覺得B比較好呢？

E的over the past decade不是有重复嗎？

In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought its western border within reach of the Pacific Ocean.

(A) In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought

(B) For about four cents an acre the United States acquired, in the Louisiana Purchase of 1803, 828,000 square miles, more than doubling the country's size and it brought

(C) With the Louisiana Purchase in 1803, the United States acquired 828,000 square miles for about four cents an acre, more than doubling its size and bringing

(D) The United States, in the Louisiana Purchase of 1803, for about four cents an acre, acquired 828,000 square miles, more than doubling the country's size, bringing

(E) Acquiring 828,000 square miles in the Louisiana Purchase of 1803, the United States bought it for about four cents an acre, more than doubling the country's size and bringing

答案是C，可是D怎麼排除呢？