Answer:
c. histogram.
Explanation:
In this case, the most appropiate way to show the results is to group the results in classes (for example from score 0 to 20, 21 to 40, 41 to 60, until 100) and show the relative frequency for each of the classes.
An histogram allows us to present this information graphically in the ways described before.
A pie chart is appropiate to show proportions.
A bar graph is similar but for discrete or non-numerical categories.
A dot plot is adequate por discrete classes and small samples.