A server administrator has configured a web server. Which of the following does the administrator need to install to make the website trusted?

IPSec (Internet Protocol Security) is used to secure IP communications, typically at the network layer, and is not directly used to make a website trusted by browsers.

Installing an SSL (Secure Sockets Layer) certificate (or more accurately, a TLS certificate) on a web server enables HTTPS, which encrypts communication between the server and clients. Browsers use these certificates to verify the website's identity and ensure data integrity, thereby establishing trust and displaying a secure connection indicator.

LDAP (Lightweight Directory Access Protocol) is used for accessing directory services and is unrelated to securing web server communication or establishing browser trust.

DNS (Domain Name System) translates domain names to IP addresses and is essential for website accessibility but does not inherently make a website trusted in terms of security.