This line chart visualizes insurance charges by age, using a dataset of individual policyholder records. It shows a positive correlation between age and medical costs, with the line rising steadily as age increases. The visualization is built with D3.js v7 in a React environment, employing SVG for rendering and a tooltip for interactive data inspection. The chart sorts the data by age, then applies linear scales for both axes, and includes axis labels and a styled tooltip that appears on hover.