A multi-line chart displays the number of music tracks per genre over time, derived from an album dataset. The visualization groups data by genre using `d3.nest()` and draws a separate colored line for each genre with `d3.line()`. Axes are built with `d3.axisBottom` and `d3.axisLeft`, scaled by `d3.scaleTime` and `d3.scaleLinear`, and rendered as SVG within a D3 v5 selection.