Factories in southern states like Georgia and Mississippi

Answer is E because only is grammatically correct.
B, C and D are wrong because they use the passive voice.
They in A, B and C don’t have clear referents as “theyâ€

I will choose E too..The pronoun they is not used confusingly and makes perfect sense..

Answer is E.

Here is why.

A) Factories in southern states like Georgia and Mississippi employed more than 300,000 workers in the late nineteenth century, but they
> Nope. They can refer to factories or workers

B) More than 300,000 workers had been employed by factories in southern states such as Georgia and Mississippi in the late nineteenth century, but they
> Nope. They can refer to factories or workers

In the late nineteenth century, more than 300,000 workers were employed by factories in southern states such as Georgia and Mississippi, but they
> Nope. They can refer to factories or workers

More than 300,000 workers had been employed by factories in southern states like Georgia and Mississippi in the late nineteenth century, but these factories
> Maybe. The word "they" is removed, but the sentence pattern does not match the original sentence. Keep it for now.

Factories in southern states such as Georgia and Mississippi employed more than 300,000 workers in the late nineteenth century, but these factories
> YES. No ambiguity + retains the original sentence pattern or structure.

I also agree with Ritesh's explanation. The independent clause should begin with factories.

OA is E....

but the explanation is different from all of you....


according to OE, E is correct a becasue the subject here is factories, so the second independent clause needs to beging with factories.

D vs E.
In D it reads that factories in states "similar" to Georgia, Missipi etc....have .experienced..xyz...

E states that factories "IN" states "Georgia, Missippi" ...have...xyz....

another E

why 1 the action took place in the past at a specific time and is over
so the simple past has to be used
2 Like should not be used in this sentence
to list the state such as has to be used

I think you misread what I wrote. There is no trick in this questions, the subject of IC need to be factories. If you pick this, rest all choices are wrong...