Based on your description of the line moving diagonally upward from left to right and having points plotted above, below, and on the line, the best statement that describes the data illustrated in the graph is:
The graph illustrates a strong positive correlation between the data.
This is because an upward slope indicates that as one variable increases, the other variable tends to increase as well. The presence of points above and below the line does suggest some variability, but overall the upward trend signifies a positive correlation.