The second option, i believe
Answer: the invention of cotton gin
Explanation:The cotton gin refers to a a machine that sets aside cotton fibers from their seeds. Therefore, the invention of the cotton gin transformed the cotton industry in the United States and demanded cheap labor force, which led to the rise of slavery in the South and to the American Civil War later.
It's debated; the credit is usually given to either Julia Ward Howe or Anna Jarvis.
Howe was born first, so if you're looking for initial efforts, I would go with her.
Hope this helps!
