Based on the description of the scatterplot you provided, it appears that there is a cluster of data points between 1 to 4.5 hours studied with test grades ranging from 77 to 98. Additionally, a dot is plotted at 0.5 hours studied with a test grade of 45, which seems to be an isolated point compared to the dense cluster.
In this case, the characteristics of the graph can best be summarized as:
There is one cluster and one outlier.
Therefore, the correct response is: There is one cluster and one outlier.