Understanding Chart Legends
A legend in a chart is a key that identifies the patterns, colors, or symbols associated with each data series. The flexibility of positioning the legend improves readability and presentation.
Explanation:
Anywhere: Modern charting software, like Microsoft Excel, Google Sheets, and others, allows users to drag and drop the legend to virtually any location within or around the chart area.
Maximising readability, and allowing users to position it anywhere within the chart
Reasons to Reject Other Options::
% Option
(2) on the corner only, (3) on the right side only and (4) on the bottom of X-axis are rigid locations, while the key answer can be set to almost any location.