A bubble chart displays the relationship between average horsepower, torque, and highway MPG for various car makes, using circle size to encode fuel efficiency and color to distinguish brands. The visualization is built with D3 v7, reading from a CSV file and rendering SVG circles with tooltips that reveal the make on hover. It uses `d3.scaleLinear` for axes and bubble sizing, `d3.scaleOrdinal` with a Turbo color palette for categorical coloring, and includes a legend showing size mappings and color-coded make labels. Styled with opacity transitions on hover, the chart updates interactively as the mouse moves.