This interactive scatterplot displays the Iris dataset, allowing users to dynamically select which variable controls the x-axis, y-axis, and point radius through three dropdown menus. Built with D3 version 7, it uses `d3.csv` to load data and `d3.scaleLinear` and `d3.scaleSqrt` for scaling. SVG circles transition smoothly between positions and sizes via `d3.transition`, while axes update through `d3.axisLeft` and `d3.axisBottom`. The code implements reusable chart and menu functions, demonstrating D3's `dispatch` event system for handling user interactions.