Plz help Which group of historical events had the most to do with abolition?

The Fugitive Slave Act, the Dred Scott decision, and the Kansas-Nebraska Act
The Compromise of 1850, the Mexican-American War, and the Gadsden Purchase
The annexation of California, the Anthony Burns case, and the Harper's Ferry revolt
The Louisiana Purchase, the Missouri Compromise of 1820, and the annexation of Texas