The most accurate answer is: The cotton gin increased cotton production so plantation owners used more enslaved labor to meet the demand.
The invention of the cotton gin by Eli Whitney in 1793 significantly increased the efficiency of cotton processing. It allowed plantation owners to clean cotton much more quickly than by hand, which made cotton a more profitable crop. As a result, the demand for cotton soared, leading to the expansion of cotton plantations in the Southern United States. To maximize production and profit, plantation owners sought to increase the workforce, which resulted in a greater reliance on enslaved labor to cultivate and harvest the cotton. This ultimately contributed to the growth of slavery in the South during the early to mid-19th century.