Final answer:
A data label (D) is used to display source data directly in a chart, offering details about individual data points for different graph types, such as line graphs for trend analysis and bar graphs for categorical comparisons.
Step-by-step explanation:
The component used to display source data in a chart directly is D. A data label. Data labels provide information about individual data points, such as the value of a bar in a bar graph, or a point on a line graph. When representing data graphically, it is essential to label the axes and use various symbols or styles to distinguish different data sets, particularly if you're plotting data for different materials or categories.
Line Graphs are particularly useful for showing how data points change over time, revealing trends in the data. On the other hand, Bar Graphs excel at showing comparisons among different categories on one axis, with a numerical or percentage value on the other.
For qualitative data, pie charts are a great way to visualize portions of a whole. However, determining which type of graph to use depends on the nature of the data—whether it is quantitative or qualitative. It is not uncommon to try different types of graphs to discern the most compelling presentation of the data.