This example visualizes a time series of monthly values (labeled A through L) using an SVG line chart with circular markers, rendered with D3.js v3. The chart maps categorical month names to the x-axis and quantitative values to the y-axis, with a distinct line path and a large numeric label for the final data point. It also demonstrates interactive hover effects: moving the mouse over a circle highlights it in red, displays its value in a temporary text label, and draws a dashed vertical guide line from the point down to the baseline. The data is loaded from a local JSON file, while scales and axes are constructed using `d3.scale.ordinal` and `d3.scale.linear`, with the line generated by `d3.svg.line`.