Four clusters of proportional circles, each labeled with a group letter (A–D), fill the entire SVG canvas without overlapping. The bubble sizes correspond to each group’s `percentResponse` value, while the cluster layout is computed using `d3.pack()` on a `d3.hierarchy()` root. Rendered with `d3.v7` in a React framework, the circles and labels are appended as SVG elements with `d3.select` and `join()`. The data source is hardcoded dummy data, with no axes or tooltips.