The administrator should perform an antivirus scan on all servers within the cluster and reboot each server, and block access to 208.206.12.9 from all servers on the network. These actions will help to remove any malware that may have infected the application server and prevent any further unauthorized traffic to the known-bad public IP address. An antivirus scan can detect and remove malicious software that may be sending data to an external source, and a reboot can clear any temporary files or processes that may be related to the malware. Blocking access to 208.206.12.9 from all servers on the network can prevent any future attempts to communicate with the malicious IP address.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 3, Lesson 3.4, Objective 3.4; Chapter 6, Lesson 6.2, Objective 6.2

The organization should retrieve the tapes from the cold site and test them to ensure they are properly maintained and usable during a DR scenario. A cold site is a location that has space and power for backup equipment, but no actual equipment installed or configured. The organization stores backup tapes of its servers at cold sites as a precaution in case of a disaster that affects its primary site. However, backup tapes can degrade over time due to environmental factors such as temperature, humidity, dust, or magnetic fields. Therefore, the organization should periodically retrieve the tapes from the cold site and test them on compatible equipment to verify their integrity and readability.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 6, Lesson 6.4, Objective 6.4

Explanation
Port 22 is used for SSH (Secure Shell), which is a secure and encrypted protocol for remote access to a server.
Port 23 is used for Telnet, which is an insecure and unencrypted protocol for remote access. Port 990 is used for FTPS (File Transfer Protocol Secure), which is a secure and encrypted protocol for file transfer. The administrator should open port 22 and close port 23 to enable SSH and disable Telnet, as SSH is more secure and reliable than Telnet. The administrator does not need to open port 990, as FTPS is not required for making configuration changes123.
References = 1: Remote Desktop - Allow access to your PC from outside your network(https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/clients/remote-deskt
2: Test remote network port connection in Windows 10 -
Winaero(https://winaero.com/test-remote-network-port-connection-in-windows-10/) 3: Windows Command to check if a remote server port is opened?(https://superuser.com/questions/1035018/windows-command-to-check-if-a-remote-server-port-is-opene

The ping command output shows that the NIC has an IP address of 192.168.1.100 and a default gateway of 192.168.1.1. However, when the technician tries to ping the default gateway, the reply comes from another IP address: 192.168.1.101. This means that there is another device on the network that has the same IP address as the default gateway, and it is responding to the ping request instead of the intended destination.
A duplicate IP address can cause network connectivity problems, such as packet loss, routing errors, or unreachable hosts. To resolve this issue, the technician should either change the IP address of the default gateway or the device that is conflicting with it, or use DHCP to assign IP addresses automatically and avoid conflicts.
The other options are not correct because they do not explain the ping output. An incorrect default gateway would cause no reply or a destination unreachable message, not a reply from a different IP address. A DHCP misconfiguration would cause an invalid or no IP address on the NIC, not a duplicate IP address on the network. An incorrect routing table would cause routing errors or unreachable destinations, not a reply from a different IP address.
References:
https://askleo.com/what_is_ping_and_what_does_its_output_tell_me/
https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/ping