Need more information sorry.
The best explanation why the area between Spain and Gaul was not part of the Roman empire until that later period was a culmination from both undesireability and difficulty in accessing this region due to its mountaineous nature. So I would wager the answer being both C and D - undesireability and difficulty in access.
Similar- involved African descent and people were not granted basic rights. Both came to an end at a point
Different- occurred in South Africa and slavery occurred in America. In Apartheid people weren’t forced into labor
I believe its D) Unemployment rates among African Americans were higher than unemployment rates among whites
