GMAT Sentence Correction (SC) | Re: Reporting that one of its many problems had been the recent

Correct me if i'm wrong.

But the reason why i chose A for this Question :

The singular pronoun "its" correctly refers to singular subject "Retailer". "their" is plural , hence we can eliminate D,E
"Recently " is an adverb and cannot modify noun "slump" . Eliminate B, C.

Now my question is would the following sent be correct :
Reporting that one of its many problems "has" been the recent extended sales slump in women's apparel, the
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