In the South, the invention of the cotton gin: O A. devastated the economy.
B. helped the plantation economy grow.
C. meant plantations needed fewer slaves.
D. led to industrialization.

B-Helped the plantation Economy grow

Explanation:

D. led to industrialization

Explanation:

It did not devastate the economy. It did not mean plantations needed fewer slave because it made plantations need more slaves. And it didn't help the plantation economy grow it only helped speed up the process of removing the seeds from the fibers.

So therefore your answer should be D. led to industrialization.

If not that then it's B. but it's most likely D.

Hope this helps:)