Answer:
The main purpose of the second paragraph is:
C. to impress the disparity of experience between citizens and slaves.
Explanation:
The second paragraph of Douglass's speech emphasizes how different it is to be a white, free person and to be a slave on the Fourth of July. After all, the nation is celebrating freedom. But, as Douglass says, he and the other slaves are "in fetters", so inviting them to celebrate freedom is an act of cruelty, of irony. He makes a point of stating that, emphasizing the disparity between the slaves' and white people's conditions. There is no reason for slaves to celebrate, which means there is no reason for Douglass to celebrate. He, a former slave, knows the pain and suffering he came from. He cannot forget and ignore that thousands of people who are still in that predicament, working to death while being mistreated, beaten, humiliated, or sold as possessions.