This visualization shows the distribution of gender categories in a heart disease dataset using a pie chart. It displays two slices representing male and female counts, with a legend showing each category and its frequency. The chart is rendered as an SVG using D3 v7, with d3.rollup to aggregate counts, d3.arc for slice geometry, and d3.pie for layout. A d3.scaleOrdinal with d3.schemeCategory10 assigns colors, while Bootstrap provides page styling. Data is loaded from a CSV file via d3.csv.