This combined bar-and-line chart displays monthly sales and profit trends using a sampled subset of the CSV data. Bar heights represent sales figures, while a red line with circular markers overlays profit values on the same axes. Built with D3 v7, the visualization uses `d3.scaleBand` for the categorical x-axis, `d3.scaleLinear` for the y-axis, and `d3.line` to generate the profit path, with points rendered as SVG circles.