What is the most important reason for speakers to use visual aids?
a. to introduce material not covered in the speech
b. to use as a crutch during a long speech
c. to delivery additional statistics
d. to keep the audience engaged

It could be letter c. delivery of additional statistics.  This is to provide more support for the topic of the speech by presenting relevant data connected with your speech.  It can also be letter d. keep audience engage because visual aids keep the audience focus on the speech and helps them understand it better.

"freedom of speech, freedom of worship, freedom from want, and freedom from fear.

the four freedoms were goals articulated by united states president franklin d. roosevelt on january 6, 1941"

its everything except for telling nonfiction and using first person