Pests - source:manhattan

[jsasipriya]

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.
A) 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.
B) 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.
C) 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.
D) 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.
E) 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.

Can someone explain why B is preferred over C?

[kvcpk]

I am unable to see anything wrong with C. But B is more concise than C.
C is wordy.

[selango]

Comma must be followed by coordinating conjuctions to avoid runon sentence.

first part says pest destroying crops...second sentence must indicate effective method is taken.This meaning is concise.

Option C is concise in meaning and comma is followed by but.

Option B the sentence is awkward.

If it is "but in the 1880s more effective pest-control methods saved the citrus industry",then the sentence is correct.