Wei gave his informative speech on meteorology. As part of the speech, he displayed an excellent three-color drawing to indicate the different temperatures in various layers of the atmosphere. When he got to the visual aid, he said, "As you can see, each layer has a different temperature," covered up the drawing, and quickly moved on. What should Wei have done to present his visual aid more effectively?
a. He should have explained the visual aid more fully.
b. He should have shown the drawing with an overhead projector.
c. He should have created a handout and passed it among the audience.
d. He should have avoided using more than two colors in the drawing.
e. He should have displayed a photograph instead of a drawing.

A visual aid can be defined as those things that add-on to the meaning of the word by using either with a picture, a drawing, or a chart. A visual aid is what can be perceived using visuals in addition to the spoken or verbal words.

For example, showing a picture of an apple to a kid while talking about it.

In the given case, Wei could have explained the visual aid of the three-color drawing that he used to indicate the different temperatures in the layers of atmosphere. He did not elaborated on the symbolism of the three colors he used to indicate the different temperatures. Though, his strategy of using visual aid was good but he lacked in explaining the visual aid.

So, the correct answer is option A.