A pie chart displays the aggregated sums of three metrics—A, B, and C—from a multiseries CSV dataset. Using D3.js v7, the code loads the data via `d3.csv`, computes totals with `d3.sum`, and generates slices with `d3.pie` and `d3.arc`. Each slice is labeled using the arc’s `centroid`, and a color-coded legend is appended manually. The SVG rendering uses ordinal color scaling and explicit positioning for the chart and legend.