PREP2-169

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

why D

我感觉so的出现大部分伴随着 that，或者是否定句中的so ... as...

那这题做何解呢？  思路是平行么？

哪位大侠能帮我分析整个题目或者所有选项呢