A network engineer must configure a Cisco ESA to prompt users to enter two forms of information before gaining access. The Cisco ESA must also join a cluster machine using preshared keys. What must be configured to meet these requirements?
A. Enable two-factor authentication through a RADIUS server and then join the cluster by using the Cisco ESA GUI.
B. Enable two-factor authentication through a TACACS+ server and then join the cluster by using the Cisco ESA CLI.
C. Enable two-factor authentication through a TACACS+ server and then join the cluster by using the Cisco ESA GUI.
D. Enable two-factor authentication through a RADIUS server and then join the cluster by using the Cisco ESA CLI.
D
Cluster configuration options must be done via the CLI on the ESA and cannot be created or joined in the GUI.
https://www.cisco.com/c/en/us/support/docs/security/email-security-appliance/200885-ESA-Cluster-Requirements-and-Setup.html