Hey, it's b because slavery was the main thing that supported the South's economy - hope this helps :)
The answers on the list are #2, #3 and #4. Those are the answers.
Answer:Alternative Title: Convention of Badgastein Convention of Gastein, also called Convention Of Badgastein, agreement between Austria and Prussia reached on Aug. 20, 1865, after their seizure of the duchies of Schleswig and Holstein from Denmark in 1864; it temporarily postponed the final struggle between them for hegemony over Germany.
Explanation:
