Not all employment selection mechanisms that have a “disparate effect,” that is, that screens out a percentage of minorities or women disproportionate to their presence in the relevant labor market, are unlawful.

(A) that is, that screens out a percentage of minorities or women disproportionate to

(B) which means, that screens out a percentage of minorities or women disproportionate with

(C) which means, that screen out a percentage of minorities or women disproportionate with

(D) that is, that screen out a percentage of minorities or women disproportionate to（D）

(E) that is, that screens out a percentage of minorities or women disproportionate with

请教一下关于THAT IS的用法，即THAT IS的使用原则，使用规律，有无固定搭配等？我只能根据单复形式猜出上题内似乎THAT IS是修饰“EFFECT”，而THAT SCREEN是修饰MECHANISMS，对吗？

请问这里的THAT IS为什么要使用？若有以前的讨论，麻烦贴一下LINKS。谢谢大家！

这个题目是mechanisms后面跟了2个定语从句。