GMAT Sentence Correction (SC) | Re: A recent study, published by the California Bureau of

I'll take a stab in trying to point out the difference between D & E.

I think most of us can see the placement of "did" is different in both A/C. The way I read it,"did " substitutes for"getting called back ".
--> One group of ppl (ethnic sounding names) had a harder time (GETTING CALLED BACK) THAN ppl (white sounding names).

D is wrong b/c the placement of "did" indicates that the 2nd group of ppl (white-sounding names)DID send their resumes ... we
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