Final answer:
Advancements in technology during the Industrial Revolution reduced the need for slave labor in the United States.
Step-by-step explanation:
During the Industrial Revolution in the United States, advancements in technology had a significant impact on the use of slave labor. The correct answer to your question is b) Technology reduced the need for slave labor.
Technological innovations such as the invention of the cotton gin by Eli Whitney in 1793 made the process of separating cotton seeds from cotton fibers faster and more efficient. This increased the demand for cotton and led to a boom in cotton production. However, it also reduced the need for manual labor in the cotton fields, as the cotton gin could do the work much faster. As a result, the use of enslaved workers in the cotton industry decreased.
Furthermore, advancements in transportation, such as the steam engine and railroads, made it easier and faster to transport goods across the country. This increased trade and economic growth, but it also reduced the need for enslaved workers to perform tasks such as loading and unloading goods.