请教一道prep07语法题！！！！

Pikosaid

Whereas the use of synthetic fertilizers has greatly expanded agricultural productivity in many parts of the world, an increase in their use can create serious environmental problems such as water pollution, and their substitution for more traditional fertilizers may accelerate soil structure deterioration and soil erosion.


                     
A.an increase in their use can create serious environmental problems such as water pollution, and their substitution for more traditional fertilizers




                     
B.an increase in their use can create serious environmental problems like water pollution, and if substituted for more traditional fertilizers, it




                     
C.if these fertilizers are used increasingly, they can create serious environmental problems such as water pollution, and if used as substitutions for more traditional fertilizers, they




                     
D.the increased usage of these fertilizers can create serious environmental problems such as water pollution, while if substituted for more traditional fertilizers, this substitution




                     
E.the increased usage of these fertilizers can create serious environmental problems like water pollution, while their substitution for more traditional fertilizers
答案是A，我选择了C。我记得“A of B”，代词是不能指代B的，不知道是不是记错了？C错在了哪里呢？

Pikosaid

新人发帖，自己先顶一下！！！！

zoeklose1

我觉得从平行的角度上来说 C and 后面缺少主语 前半句也很别扭