Answer:
Option: d. States' rights.
Step-by-step explanation:
The South economy depended on agriculture could not survive without slavery. States’ rights was a doctrine given by southern politicians to protect slavery. The South wanted to protect the slave system from the threatened federal law (the North) that would force abolition upon Southern states. The people in the South believed in the system of slavery because they generated wealth from them by forcing them to work in the cotton plantations.