一道gwd题，求解！！

richygogogo

By the same techniques used for genetically enhancing plants, making them disease- or pest-resistant, researchers have been able to increase the amount of protein in potatoes, sweet potatoes, and tobacco.

A.By the same techniques used for genetically enhancing plants, making them
B.With the same techniques to genetically enhance plants, so that they are
C.Employing the same techniques used to genetically enhance plants so that they are
D.Employing the same techniques to genetically enhance plants, which makes them
E.Employing the same techniques for genetically enhancing plants that make them
这道题我想问b选项，with...., so that...., researchers have been able to.....这是一句完整的话吗？so that是一个句子了，后面的researchers又是一个句子，是这样吗？？

Fiona09

b项 句子都杂糅到一起了。。。

with...to的用法不对，一般是with...V+ing作伴随状语。

researchers have been able to...后面是主句。

so that是用来引导目的状语从句或结果状语从句的。