Sentence Correction

Pests had destroyed grape, celery, chili pepper crops, sugar beet and walnut in the region, but in the 1880s, more effective pest-control methods saved the citrus industry.

Pests had destroyed grape, celery, chili pepper crops, sugar beet and walnut in the region, but in the 1880s, more effective pest-control methods saved the citrus industry.

Pests had destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region, but in the 1880s, more effective pest-control methods saved the citrus industry.

Pests had destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region, but more effective pest-control methods that were introduced in the 1880s saved the citrus industry.

In the 1880s, pests destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region and more effective pest-control methods saved the citrus industry.

In the 1880s, more effective pest-control methods saved the citrus industry from what was destroying grape, celery, chili pepper, sugar beet and walnut crops in the region.

IMO-C

That's what I had too but that is incorrect.

IMO B

Past perfect is right here, because the order of actions matters. C is wrong because it is unclear to what 1880s is related. In D it is clear the 1880 is related to introducing the methods.
In A and alike answers "crops" is not in the right place, "grape, celery, chili pepper, sugar beet and walnut" modifies crops.

So i think D is the answer. What's the OA ?

IMO D..

IMO E.

the best answer is B, because we have to opposit clause so we need a switch conjunction "but". and it uses crops in the right position collectively for the previous nouns.

OA: B.

"in the 1880's" should only refer to citrus while in C, this is not clear

I'm stuck between B and E. what happens with E?

Pests had destroyed grape, celery, chili pepper crops, sugar beet and walnut in the region, but in the 1880s, more effective pest-control methods saved the citrus industry.

Pests had destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region, but in the 1880s, more effective pest-control methods saved the citrus industry.<- But shows the contrast...

Pests had destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region, but more effective pest-control methods that were introduced in the 1880s saved the citrus industry.< - No one knows when the methods were applied.. Incorrect

In the 1880s, pests destroyed grape, celery, chili pepper, sugar beet and walnut crops in the region and more effective pest-control methods saved the citrus industry.<- It shows pests destroyed and at the same time methods saved the crops...

In the 1880s, more effective pest-control methods saved the citrus industry from what was destroying grape, celery, chili pepper, sugar beet and walnut crops in the region.<- wordy .. incorrect...