Answer:
Option: d. benefited in part from a sense of unity bred by criticism from outsiders.
Explanation:
The Southern planters criticized by the outsiders like the North over the practice of slavery. In the northern states, people have always rejected slavery describing it as an evil practice by having anti-slave policies and beliefs. The rich and poor Southern planters categorized as the slave practitioners by the northern states, who forced the African American slaves to work in fields, also punished them harshly.