The "ps" command is used to display information about the processes running on a system. The "-ef" option shows the full format listing, which includes the process ID, the user, the CPU and memory usage, the command name, and other details. This can help the engineer identify which processes are consuming the most resources and causing the degraded performance of the server. The other options are either invalid or irrelevant, as they do not provide the necessary information or perform the required action. References := Cisco Cybersecurity