A row of five gray SVG circles responds to mouseover events by turning orange, demonstrating D3.js event handling with a simple hover interaction. The example renders static circles via SVG and uses d3.selectAll('circle') with the .on('mouseover') method to attach listeners, logging the event target to the console while changing the fill style. Mouse clicks remain unimplemented, as only the hover state is wired up, and the status text below the visualization is not updated programmatically.