This interactive bar chart displays the absolute frequencies of categorical values from a dataset of student grades and degree programs. Users can switch the category displayed on the x-axis via a dropdown menu, which triggers a re-render of the chart. Built with D3 v5 and React, the visualization uses `d3.nest()` for aggregation, `d3.scaleBand()` and `d3.scaleLinear` for axes, and animated transitions on hover to highlight bars and show value differences. Tooltips appear on mouseover, while axis labels and titles update dynamically.