GMAT Sentence Correction (SC) | Re: In the Champagne region of France, wine growers still

In the Champagne region of France,wine growers still harvest grapes as they have done for centuries, by carefully hand-picking their crop and storing their precious fruit in specially aged casks.

I am confused between Option (A) and (E). I need more explanation.
A) wine growers still harvest grapes as they have done
E) wine growers still harvest grapes as they did

Activity of wine growers i.e. grape harvesting done in past is compared with that in present. Though they still doing the same,