The primary requirement is to visualize the "composition of total sales amounts" across different channels. A pie chart is the most suitable visualization for this purpose as it is specifically designed to show part-to-whole relationships. Each slice of the pie would represent a sales channel (Digital, Store, Online), and the size of the slice would be proportional to its contribution to the total sales, clearly illustrating the composition.

A. Pivot table: A pivot table is a tool for data summarization in a tabular format, not a graphical visualization designed to show proportional composition.

C. KPI card: A Key Performance Indicator (KPI) card is used to display a single, aggregate metric (e.g., total sales), not the breakdown or composition of that metric across categories.

D. Box plot: A box plot is used to display the statistical distribution of numerical data (e.g., median, quartiles, outliers), not the proportional contribution of categories to a total.

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1. Microsoft Power BI Documentation. (n.d.). Pie charts in Power BI. Microsoft Docs. Retrieved from the official Power BI documentation on visualization types. In the section "When to use a pie chart

" it states

"Pie charts are a great choice... To show proportions." This directly aligns with the question's need to show the composition of total sales.

2. Wilke

C. O. (2019). Fundamentals of Data Visualization: A Primer on Making Informative and Compelling Figures. O'Reilly Media. In Chapter 10

"Visualizing proportions

" Section 10.1

"Pie charts

" the author states

"A pie chart represents the whole of a given quantity as a circle

and the parts as wedges of that circle. The parts are sized by their relative contribution to the whole." This is a standard use case taught in data visualization curricula at institutions like the University of Texas at Austin

where the author is a professor.

3. University of Washington. (n.d.). Data Visualization: Basic Principles. Course materials for DATA 512: Data Visualization. The course materials explain that pie charts are used to show the "relative shares of categories that sum to a whole

" which is precisely the task of showing the composition of sales channels.