This D3.js v4 visualization presents a boxplot of BMW model fuel efficiency (mpg) across model years 2009–2012, sourced from boxplot.csv. It summarizes the distribution per model using d3.nest() to compute quartiles and the interquartile range, which are drawn as a box-and-whisker plot via SVG shapes. Individual data points are overlaid as red circles with a fixed x-offset, and hover interactions (configured via d3.select and tooltip transitions) reveal exact mpg values. The chart uses d3.scaleBand for the categorical axis, d3.scaleLinear for the numeric axis, and d3.axisBottom/Left for tick marks.