Which of the following is NOT a formatting option for sparkline charts?

Sparklines are compact, simple charts typically used to convey trends within a dataset in a visually concise manner. When it comes to formatting options for sparkline charts, there are specific functionalities available that enhance their visual representation and convey the intended message more effectively.

Selecting an icon, setting scaling, and setting threshold colors are all valid formatting options for sparklines. Selecting an icon allows users to represent data with visually distinctive symbols, enhancing clarity. Setting scaling adjusts the relative sizes of the data points in the sparkline, making it easier to compare values visually. Setting threshold colors applies specific color schemes to data points based on predefined criteria, allowing for quick visual assessments of performance against benchmarks.

However, changing the chart type is not a formatting option for sparkline charts. Sparklines themselves are inherently defined by their design, and users do not switch between different chart types (like bar, line, or area) within a sparkline framework. This lack of flexibility in changing chart types is a characteristic unique to sparklines, as they are meant to provide a straightforward visualization without the complexities associated with fully-fledged charts.