Slavery is a type of labor, in which the person owns another person for different kinds of work. It was very famous in the middle ages. The slave could be anybody, and can employed anywhere.
The correct answer is:
Option 2. Extension of Slavery
Slavery was characterized by several national movements:
1. The compromise of Missouri and Maine. Missouri was forced into the Union as a slave state, while Maine was declared a free state.
2. The state of California was admitted to the Union as a free state in the 1850s. The arising slavery issue in the middle ages, California was incorporated in the union as a free or non-slave state.
3. The Kansas-Nebraska act was to decide the sovereignty based on the popularity of the state. The Kansas slavery would violate the Missouri compromise, thus, Missouri had kept the union for the last 34 years.
Thus, the correct answer is the Extension of Slavery.
To know more about slavery, refer to the following link:
https://brainly.com/question/9331183