GWD-3-Q11语法点求助 as because x as because y

dength

Retailers reported moderate gains in their November sales, as much because of their sales of a year earlier being so bad as that shoppers were getting a head start on buying their holiday gifts.
a. of their sales of a year earlier being so bad as that
b. of their sales a year earlier having been as bad as because
c. of their sales a year earlier being as bad as because
d. their sales a year earlier had been so bad as because  
e. their sales of a year earlier were as bad as that

各位NN，这道题答案选的D，这个没有太多疑问。我比较不理解的是as much because x as because y 这个语法点。我知道as可以做连词，但是具体来说的话as是并列连词还是从属连词，还是两种都可以做呢？这里的感觉像是在做并列连词连接了两个becuase从句。但是我好像没有查到as能做并列连词，只了解as作为从属连词可以引导多种类型的从句。不知道大神们能不能帮我解答一下。

dength

自顶，求大神解答