What is a common function of a proxy server?

What is a common function of a proxy server?

• to store frequently accessed web pages on the internal network
• to control who is permitted to access the internal network
• to detect malicious signatures by monitoring traffic that is entering the internal network
• to provide access to a shared pool of configurable computing resources
  

  Explanation: A proxy server is often responsible for caching web pages frequently accessed by internal users. If another internal user requests any of the stored pages, the proxy server can quickly provide the stored web pages to the internal user instead of sending the request over the Internet to the original web server.