Meanwhile, the South continued to grow as an agricultural power. Eli Whitney’s invention of a cotton gin (short for “engine,” or machine) in 1793 made it possible for Southern farmers to produce cotton more profitably. The emergence of a Cotton Kingdom in the South—and thus the need for more field labor—contributed to the expansion of slavery. Between 1790 and 1820, the enslaved population increased from less than 700,000 to over 1.5 million. In the North, things were different. By 1804 states north of Delaware had either abolished slavery or had enacted laws for gradual emancipation. Slavery declined in the North, but some slaves remained there for decades. Select the answer choice from the list to complete the sentence correctly.

The cotton gin led to the expansion of slavery in .

a
Great Britian
b
New England
c
the North
d
the South