Sentence Correction

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