Answer:
C. The length of the presentation and D. The authority of the quoted experts
Explanation:
The answer for your question is actually D because when talking about context its best you have quoted experts but in general I would say both.
For your question though so you don't get confused on which answers it is its
Carletta Wilson brilliantly portrays Abraham Lincoln as a man who is gifted with words, stating that he “inspired unity with his Second Inaugural Address” and that he “exhibited perfection in speech with the Gettysburg Address.”
The first option gives the opinion that Lincoln "is gifted with words." She then supports this idea using direct quotes about the impact his words have had on his audience. The second option about the Emancipation Proclamation is a fact, not an opinion. The third option does give an opinion, but does not use any evidence to support the opinion. The last choice is just terrible writing.
My best guess would be generalization