This bubble chart visualizes the correlation between three metrics for various hashtags: number of mentions, engagement rate, and reach. Each circle's x-position maps to mentions, y-position to reach, and its radius encodes engagement rate, with color distinguishing the hashtag. It includes a legend for engagement rate values and a color legend for hashtags. Built with d3.v7, it uses `d3.scaleLinear`, `d3.scaleOrdinal`, and `d3.schemeCategory10` for encoding, and renders as SVG with interactive tooltips on mouseover. The data comes from the provided `bubblechart.csv` file.