Which of the following best describes the role of a proxy server?

A proxy server serves as an intermediary between internal computers and external networks, which is a key function that enables it to perform various tasks such as filtering content, improving security, and managing requests. When a user requests a resource from the internet, the request is first sent to the proxy server. The proxy then forwards the request to the external network on behalf of the user, receives the response, and sends it back to the user. This setup can help in enhancing privacy, as the user's IP address is not directly exposed to the external resources. Additionally, it can cache content for faster access and apply security measures by inspecting and filtering incoming data.

In contrast, proxy servers do not inherently encrypt data, distribute network load, or provide direct access to the internet without any intermediate layer. While they potentially can work with encryption protocols and function in load balancing roles through specific configurations, their primary characterization is as an intermediary which reflects the overarching function described in the correct choice.