To me, both the options appear to have an awkward structure. Please post in the full question with all the options.

Thanks for responding...!

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

A) wine growers still harvest grapes as they have done
B) the wine grower still harvests grapes as he was
C) wine growers still harvest grapes as was done
D) wine growers still harvest grapes as has been done
E) wine growers still harvest grapes as they did

The correct option is A.

I did not understand the explanation given for options C & D- i.e., they make the sentence switch from active (harvest) to passive (as was done, as has been done).

poonam197 wrote:Thanks for responding...!

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

A) wine growers still harvest grapes as they have done
B) the wine grower still harvests grapes as he was
C) wine growers still harvest grapes as was done
D) wine growers still harvest grapes as has been done
E) wine growers still harvest grapes as they did

The correct option is A.

I did not understand the explanation given for options C & D- i.e., they make the sentence switch from active (harvest) to passive (as was done, as has been done).

I don't have any explanation for active to passive switch, but let's see the options like this: what should be the subject of "was done" and "has been done?" Harvest, correct?

Let's write them down seperately:

As harvest was done for centuries,...
As harvest has been done for centuries,...

Now let's append the last part in the given sentence?

As harvest was done for centuries, by carefully handpicking their crop and storing their precious fruit in specially aged casks.

As harvest has been done for centuries, by carefully handpicking their crop and storing their precious fruit in specially aged casks.

Can you see the issue now? Think what is their referring to in the above sentences? Compare above sentenses with the below one:

As they have done for centuries, by carefully handpicking their crop and storing their precious fruit in specially aged casks.

Now 'their' is clearly referring to 'they', which in turn referring to wine growers.

C) wine growers still harvest grapes as was done
D) wine growers still harvest grapes as has been done

First, the extracts above do not specify as to who is doing the action(?) i.e they do not point towards the subject, the 'wine growers'.

Further 'was' in C seems as if to suggest that the activity(harvesting) was prevalent in the past, discontinued afterward, and is again prevalent nowadays...the sentence however does not suggest any such order!

Both C as well as D are passive in my opinion.

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

A) wine growers still harvest grapes as they have done
B) the wine grower still harvests grapes as he was [As there is a plural noun "growers" in the main sentence, using singular distorts the meaning of the sentence. Besides, "as he was" means that he was the harvest of grapes.]
C) wine growers still harvest grapes as was done ["as was done" by whom? Unnecessary use of passive.]
D) wine growers still harvest grapes as has been done [Unnecessary use of passive and without agent.]
E) wine growers still harvest grapes as they did [As the trace of the work is still prevailing, we should not use the past simple.][/b]