A stacked bar chart displays sales data across cities for a selected customer segment, with bars divided by product sub-category. An interactive dropdown filters by segment, while a checkbox toggles between sorting cities alphabetically or by total sales. Built with React and D3 v5, the visualization uses `d3.csv` to load data, `d3.stack` for stacking layers, and transitions to animate updates. SVG rects and axes render the chart, with text labels showing quantities above each bar.