Which data type is commonly used for passing small amounts of information between a web server and a client?

The chosen answer is correct because cookies are specifically designed for the purpose of storing small amounts of data that can be sent between a web server and a client. Cookies are typically used to keep track of user sessions, store user preferences, and maintain other small pieces of information that need to be transmitted with HTTP requests.

When a client (like a web browser) makes a request to a server, cookies can be automatically included in the headers of those requests, allowing for seamless communication and state management between the server and the client.

In contrast, sessions are primarily used on the server-side to store information temporarily for user interactions during a browser session and typically require a cookie to identify the session on the client-side. Local storage and IndexedDB are browser-based storage solutions that allow for larger quantities of data to be stored on a client but are not inherently transmitted between the client and server with each HTTP request, making them less suitable for this particular scenario of passing small amounts of information.