A grouped bar chart displays the distribution of letter grades (A through F) across five self-reported stress levels, using counts from a CSV dataset of student grades and mental health. The visualization reveals how grade frequencies vary by stress category. The code uses D3 v7 with `d3.csv`, `d3.rollups`, and `d3.scaleBand` for the nested bar layout, plus SVG rendering for all marks and axes. An ordinal color scale maps grades to categories, with a legend provided.