King opened his speech with eloquent paragraphs, speaking about the Constitution, the Declaration of Independence, the Proclamation of Emacipation, which created the credibility of the speaker, and the foundation of the historical context. Furthermore, in his speech, he used a metaphor, vivid imagery, for a clear and powerful message. He emphasized the key points of his messages with repetition, because repetition helps the flow of presentation and rhythm.
The answer is: c.
