A dropdown menu allows a user to select a year from a dataset of module codes, values, and years, triggering an animated update of a stacked bar chart displaying the total value per module. The chart, rendered as SVG, uses d3 transitions to smoothly animate the repositioning and resizing of the stacked bars and their corresponding value labels. The visualization leverages d3's `data.csv`, `scaleBand`, `scaleLinear`, `scaleOrdinal`, and `d3.stack` to process the data and generate the layered bar representation.