Answer:
B. Many nations had already abolish slavery
Step-by-step explanation:
Because of the pressure of European bourgeoisie who led the Industrial Revolution, many European nations liberated their slaves, so that they integrated a wage labor and consumer market that the bourgeois needed at that moment. Because of this, the proclamation of emancipation was very successful in Europe. Through the proclamation of emancipation the European bourgeoisie expected an increase in the American consumer market.