CompTIA Data+ DA0-002 (V2) Practice Question

The correct answer is a legend. A legend serves as a key for a chart, identifying what the different colors, patterns, or symbols used in the visualization represent. In this scenario, with four different product lines each shown as a uniquely colored line, a legend is essential to connect each color to its corresponding product line, making the chart understandable.

• Data labels are incorrect because they display the specific value of individual data points on a chart. While they add precision, they do not solve the core problem of identifying which product line each colored line represents.
• A title is incorrect because it describes the overall purpose and content of the chart (e.g., 'Quarterly Sales by Product Line') but does not explain the individual elements within it.
• Gridlines are incorrect as they are background lines that help the viewer's eye align data points with the values on an axis. They provide a frame of reference for values but do not help in distinguishing between data categories.