This example demonstrates a React-based dropdown menu that lets users select a car brand from a list of options. The selection updates the component’s state and reflects the chosen value in the dropdown. The code uses React’s `useState` hook for state management and a custom `Dropdown` component that renders a native `<select>` element. The visualization is rendered with D3.js v6 and styled with large fonts, though no graphical data output is shown beyond the control itself.