Answer:
a. banks
Step-by-step explanation:
The slaves in the South were put to work in places where the majority of the population either didn't wanted to work, or where there was a lack of labor force. Whichever the way, the slaves were only allowed to work manual labor, usually the hardest one, so they were mostly included in the agriculture, and some in the iron works, or laundries. The banks were definitely not a place where they were allowed to work, and even if they were, they would have not been able to because they were not educated for such a work.