This D3.js (v5) visualization renders the classic Iris flower dataset as a scatter plot, displaying sepal length against sepal width. A dropdown menu above the chart offers "Sepal" and "Petal" options, which currently only log selections to the console. The plot uses `d3.scaleLinear` for axes, which are rendered with `d3.axisLeft` and `d3.axisBottom`. Data is loaded from a local CSV file, and circles are appended directly to an SVG element, with the `d3.select` API managing the SVG and menu interactions.