This visualization uses a stacked bar chart to display average marks for modules within different module groups, with each bar colored by its module code. The code employs D3 v3’s `d3.nest()` and `d3.layout.stack()` to group and stack data from the Attendance.csv file, while `d3.scale.ordinal()` and `d3.scale.linear()` map the categorical and numeric axes. A color legend is rendered using the `d3-legend` library, and the SVG output is built with React.