This interactive scatterplot lets users explore the relationship between car horsepower and weight from the auto-mpg dataset, with a dropdown menu to select which numerical column drives the x-axis values. The visualization uses D3 v6 to render SVG circles with semi-transparent red fills, scaling axes with d3.scaleLinear and extent. Axes are drawn using d3.axisBottom and d3.axisLeft, and the custom dropdownMenu module populates the select element with all data columns.