Combine the two ideas into a single sentence These results are a reflection of the answers test takers provide about their traits, they rarely reveal big surprises

The correct answer is A. A graph showing the improved scores over the past five years

Explanation:

In speeches, presentations or demonstrations it is common for the speaker to use visual tools or aids that help him or her to support with evidence the ideas presented to the audience, these tools allow the speaker to show the audience what is being said is valid and true. The type of visual aid depends mainly on the purpose of the speech or presentation, this means if the purpose of the speaker, in this case, is to show the improvement in the student's math scores over the past five years the visual aid needs to explain the way in which the math scores have changed.

Because of this, the more suitable and effective visual aid, in this case, is a graph, as graphs are diagrams useful to represent the relation between two or more elements which in this case is the relation between the years and the math grades obtained during that year. Thus, the visual aid that would effectively support the speaker argument is "A graph showing the improved scores over the past five years" as this type of visual aid shows the audience the way the math scores changed during the years which is the main purpose of the speaker, and which cannot be accomplished by using other types of visual aids.