What is one effect of Douglass's use of contradictions in the introduction of his speech?

A.
The contradictions show that Douglass is difficult to understand in this speech.

B.
The contradictions underscore his lack of preparation.

C.
The contradictions highlight the complexity of the situation of slavery.

D.
The contradictions challenge his audience's assumptions about him.

C. The contradictions highlight the complexity of the situation of slavery.