A bar chart displays the average score for each favorite subject, derived from a CSV dataset via `d3.csv` and aggregated with `d3.rollup`. Bars animate upward from the baseline using `transition().duration(900)`, and hover interactions change fill color and show a tooltip. The visualization uses D3 v7 with SVG rendering, including axes generated by `d3.axisBottom` and `d3.axisLeft`, while subject labels are rotated for clarity. The title and axis labels are added as SVG text elements, and all data is filtered for valid subject and score entries before aggregation.