The correct answer should be D. Juneteenth
The Emancipation Proclamation declared that slaves from all rebellious states were free from that point on, however, Texas was not a rebellious state and wasn't in the war so they still had slavery on a technicality. Juneteenth is a day in June when Texas abolished slavery and proclaimed that all slaves would be free in its territory, which was a sign that if they could do it then everyone can do it.