sc上的一道题不懂，麻烦谁帮忙解释一下

School integration plans that involve busing between suburban and central-city areas have contributed, according to a recent study, to (significant increases in housing integration, which, in turn, reduces )any future need for busing.

A. significant increases in housing integration, which, in turn, reduces

B.sighificant integration increases in housing, which, in turn, reduces

C.increase housing integration significantly, which, in turn, reduces

D.increase housing integration significantly, in turn reducing

E.significantly increase housing integration, which, in turn, reduce

the key is A. who can explain me the other choices?

自己顶一下

哦,知道了,谢谢.