Lemme get the answer options...
There are no options given, but historically speaking it was the invention of "Cotton Gin".
A cotton gin was a revolutionary invention which enabled people to
easily separate cotton fibers and seeds; previously it used to take a large
time sorting it manually. The inventor behind this was <span>Eli Whitney. The processing was made easy but
still slaves were needed to grow cotton.</span>
I believe it's C. Skilled Labor.
