Comprehension
the questions below refer to the selection“from specimen days.”
the president, when seen by the speaker, was traveling by
a. car
c. horse and carriage
b. boat
d. train

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

b

explanation: