This line chart visualizes the average car price per year, using data from a CSV file loaded via `d3.csv`. The code groups the data by year using `d3.rollups` and computes the mean price, then renders a monotone-curved line via `d3.line` with `d3.curveMonotoneX`. Orange dots mark each year’s average, with hover tooltips. Axes are generated with `d3.axisBottom` and `d3.axisLeft`, and the SVG chart includes labeled axes for year and average price in USD.