A 3D scatter plot displays the relationship between product cost price and selling price using purple circles. The visualization uses D3.js v4 with an SVG rendering approach, mapping cost price to the x-axis and selling price to the y-axis through linear scales. Data is loaded via `d3.csv` from a GitHub-hosted dataset. The chart employs `d3.axisBottom` and `d3.axisLeft` for axes, while circles are appended with `attr` for positioning and styling, though the title's "3D" aspect is not implemented in the code.