A bar chart displays average marks per subject, computed from a CSV dataset of student scores. The visualization uses D3.js v6 to load the data, calculate averages with `d3.mean`, and render SVG rectangles scaled by `d3.scaleBand` and `d3.scaleLinear`. Axes are added via `d3.axisBottom` and `d3.axisLeft`, with labels and a title. Bars turn orange on hover through CSS, and the chart includes rotated x-axis tick labels and clear axis annotations.