This bar chart displays the average calorie count for menu items at several fast-food restaurants, using data from a CSV file. The visualization encodes the average calories on the y-axis and restaurant names on the x-axis using rectangular bars. Built with React and D3.js (v7), the code uses `d3.csv` to fetch data, `d3.rollups` and `d3.mean` for aggregation, and `d3.scaleBand` and `d3.scaleLinear` for axes, rendering the final chart as SVG.