19. 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（B）
(E) their circuits more complex, both the power of the chips and the electronic devices they drive have
我想说的是D，E 中的THEIR 是不是已经变成指代the etched lines 了，或者说是已经优先指代the etched lines 了？ MBABARAVE 说 WHEN YOU FIND PRONOUN AS SUBJECT IN A CLAUSE THE PRONOUN FIRSTLY REPRESENT THE SUBJECT OF MAIN CLAUSE .
不知道大家能不能详细说一下，谢谢了：） | 
