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

[spoiler]OA: Later[/spoiler]