Q29:

Most of LACE w:st="on">PortugalLACE>’s 250,000 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.

1. year toward the cost of higher education, previously paying $7 per year
2. year toward the cost of higher education, for which was previously paid $7 per year
3. year, compared to the previously $7 per year, toward the cost of higher education
4. year toward the cost of higher education, instead of the $7 per year required previously
5. year as opposed to the $7 per year required previously for the cost of higher education

答案为D， 不明白B为什么不好?

请NN帮忙解答，谢谢............