This example shows a React-based dropdown menu for selecting a pet from a list of predefined options. The selected value is displayed in the console, demonstrating state management. The code uses React hooks (`useState`) to track the current selection and ReactDOM to render the application. A reusable `DropDown` component accepts options, an id, and a change handler, mapping over the options to generate `<option>` elements within a `<select>` tag. The example highlights splitting React components into separate ES6 modules and uses D3 v5 for utility purposes, though no visualization is rendered.