大全20－19（没找到讨论） 以及 求助代词指代不清

As the etched lines on computer memory chips have become thinner and the chips’ circuits more complex, both the power of the chips and the electronic devices they drive have vastly increased.

(A) the chips’ circuits more complex, both the power of the chips and the electronic devices they drive have

(B) the chips’ circuits more complex, the power of both the chips and the electronic devices they drive has

(C) the chips’ circuits are more complex, both the power of the chips and the electronic devices they drive has

(D) their circuits are more complex, the power of both the chips and the electronic devices they drive have
   

(E) their circuits more complex, both the power of the chips and the electronic devices they drive have

答案是B，请问A为什么错呢？是因为A的the power of 会有歧义？

还有就是A,B的they指代谁？我觉的指代不清。事实上我对什么时候是指代不清一头雾水

关于指代不清，希望有NN能讲解一下

A
both [the power of the chips] and [the electronic devices they (the chips) drive] have increased.
the power increased没有问题，但是devices increased什么意思呢？

我认为they指代the chips

大家讨论讨论～

觉得they指代chips

a,b的由于both的位置不同造成意思不同，a是(the power of the chips)和( the electronic devices they drive) increased, b是the power of (both the chips and the electronic devices they drive) increased, b更符合句意