Based on the description provided, the map likely depicts the Missouri Compromise. This legislation, enacted in 1820, aimed to maintain a balance between free and slave states as the United States expanded westward. The references to "Slave states," "Free states," and "Territories" align well with the Missouri Compromise's provisions, which established a line of demarcation for the permissible spread of slavery in the western territories.
The other options, while related to slavery and territorial expansion, do not specifically correspond with the way the territories and states are labeled on the map you described.