This stacked bar chart displays sales volumes across five regions (North, South, East, West, Central) broken down into five product categories. The horizontal bars are segmented by category, with each region’s total sales represented on a linear scale. Using D3 v7, the code applies `d3.stack()` to aggregate category values, maps regions to a band scale for the y-axis, and retrieves data from `sales_data.csv`. Interactive tooltips appear on mouseover, and a legend is rendered via SVG rectangles and text elements.