请教关于平行结构：SC大全396

396.        In recent years cattle breeders have increasingly used crossbreeding, in part that their steers should acquire certain characteristics and partly because crossbreeding is said to provide hybrid vigor.

(A) in part that their steers should acquire certain characteristics

(B) in part for the acquisition of certain characteristics in their steers

(C) partly because of their steers acquiring certain characteristics

(D) partly because certain characteristics should be acquired by their steers（E）

(E) partly to acquire certain characteristics in their steers

OG的解释说明这是考平行结构(parallelism)并认为选项是E。可安装GMAT一贯对平行结构中前后成分结构应保持一致的“高标准严要求”，这里就说不过去了。因为and连接的前后两部分虽然都用partly来引导，但前面是不定式、后面是原因状语从句，并不“平行”啊。

而D选项好歹也是原因状语从句，而且我并没有感觉出来这个passive voice哪里有OG的解释里批评的"awkward and illogical"？

所以我觉得该选D。请大牛帮忙理解一下OG里选E的解释。