Im not 100% sure but i think it is A.
Translate this to english and I can help you
Service in the army for the war and they helped fight.
Answer:
Slavery is the practice of owning slaves (workers who are treated poorly and don't make any money, forced labor). It still continues on today so there is no such thing as "did" but I think mostly because it is free labor. Slavery is still practiced all around the world today.
