请教一道我觉得“指代不清”的题目

shuaihere

Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete one day may be partners the next.


A.    Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete
B.    Although the lines of competition are clearly defined in industries that are more established, they are blurred and indistinct in the Internet industry, as competing companies




这道争议题（出自GWD）大家在到底是选A还是选B中一直没有定论。我想问的是。。。。我觉得，A,B这两个选项中,they之前都同时出现了lines of competition和established industries这两个复数名词，因此犯了“指代不清”这个错误啊，就是不知they是指代前者还是指代后者，为什么这两个选项还能成为正确答案呢？