This bubble chart visualizes the correlation between number of mentions, engagement rate, and reach for various hashtags. Each circle’s position maps mentions on the x-axis and reach on the y-axis, while its radius encodes engagement rate and its color distinguishes hashtag categories. The visualization uses D3 v7’s `scaleLinear`, `scaleOrdinal`, `d3.csv`, and event handlers for interactive tooltips. Axes, a legend for engagement-rate sizes, and a color legend are rendered in SVG, with hover effects that increase opacity and display detailed tooltip data.