A pie chart visualizes sales by category from a CSV dataset, using d3.csv to load values. The SVG graphic displays category labels on each slice via d3.arc and a legend on the right. D3 v7’s pie generator computes the arc angles, while d3.scaleOrdinal with schemeTableau10 assigns colors. The code uses `d3.pie()` and `d3.arc()` to generate paths, with tooltips added as titles, and a legend built from rectangles and text elements.