An interactive donut chart visualizes the distribution of income categories from a CSV dataset, with each slice labeled and colored by category. Hovering over a slice displays a tooltip showing the percentage of the total that slice represents. The chart is rendered as an SVG using D3 v5, employing `d3.pie()`, `d3.arc()`, and `d3.scaleOrdinal()` for layout and color encoding, with mouse events to update the tooltip’s opacity and position.